Quiet aerofoils of the next generation

Lead Research Organisation: Brunel University London
Department Name: Mechanical and Aerospace Engineering

Abstract

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Description The start date of this EPSRC project is officially at 30 April 2016. A suitable candidate for the postdoctoral research fellow (Dr Seyed Mohammad Hasheminejad) has been recruited in May 2016. Because Seyed is a non-EU national, he needs to apply the Tier-2 visa before he could come to the UK and work on this project. Although the application form and the supporting documents were submitted in good times by the postdoc from Singapore, the approval process took longer than expected due to several issues. He finally obtained his clearance to come to the UK in early December 2016, which is the date when he started to work on this project.

In order to maintain the progress, I was supported by two of my PhD students (Philip Woodhead and Auris Juknevicius) between May - December 2016 to set up some experiments and obtained important results pertaining to this project. The research team then expands upon the arrival of the post-doc (Seyed) in December 2016, and Seyed worked full time for 24 months period on this project. There are five areas that can be summarised as the key findings for this project:

(1) Philip and I have invented and developed in this project the spanwise-wavy concept for the serrated trailing edge to improve the broadband noise reduction of aerofoil at low pressure loading condition. After testing repeatedly in the aeroacoustics facility, larger broadband noise reduction can indeed be achieved by the spanwise-wavy serration than the conventional "non-flap" serration at high frequency between 2 - 20 kHz, thus proving that this new concept represents the next level of the owl-inspired serration technology. In addition, the scientific mechanism for the noise reduction by this new concept is very interesting and has the potential to improve the understanding of the noise reduction by serration. We have presented the results in the Aviation 2017 (23rd AIAA/CEAS Aeroacoustics Conference, 5-9 June 2017). The URL of the proceeding is https://arc.aiaa.org/doi/abs/10.2514/6.2017-4175 . We have also submitted a related journal article to the Experiments in Fluids, which is currently under review.

(2). The owl also inspire the use of serration on the leading edge to reduce the turbulence interaction noise. So far, these serrations were formed by cutting the sawtooth/wavy pattern directly into the aerofoil main body. Auris and I have developed a new "add-on" concept to insert the thin flat plates (with serration pattern) into the leading edge of the aerofoil. After an extensive test campaign, we discovered that the significant level of interaction noise reduction can be achieved by the flat plate concept. We have also tested a novel configuration, namely the "curved serration" and can confirm that it can outperform the counterpart in the straight serration. Overall, the "add-on" and "curved-serration" concepts have a great advantage in terms of the ease of implementation and manufacturing, which has a potential to attract the fan-based industries. We have present the results in the Aviation 2017 (23rd AIAA/CEAS Aeroacoustic Conference, 5-9 June 2017), the URL of the proceeding can be found in https://arc.aiaa.org/doi/abs/10.2514/6.2017-3491, and published in the Journal of Sound and Vibration (2018) https://doi.org/10.1016/j.jsv.2018.02.038

(3). Seyed works on a novel trailing edge concept that employs the fractal-serrated configuration, which exclusively applies to the cut-in type serration. This represents a very effective configuration because the "fractals" not only can stop the formation of the vortex shedding (thus minimising the narrowband tonal noise), but also enhance the serration effect such that the turbulent broadband noise can be reduced further. This configuration can also be easily manufactured and fabricated, which should attract the attention from the industries. We also investigate the complex flow mechanisms that are responsible for the above features using two-point correlation on the velocity field. With an improved understanding of the physical mechanism of the noise reduction by fractal-serrated trailing edge, it is possible to suggest the design guideline for an optimised fractals that cover a wide range of flow conditions. The work is presented in the Aviation 2018 (24th AIAA/CEAS Aeroacoustic Conference, AIAA 2018-3132) https://doi.org/10.2514/6.2018-3132 . We are now preparing the submission of journal version of this work.

(4) Seyed has also conducted the experiments to investigate the use of leading edge serration to mitigate the bluntness-induced vortex shedding tonal noise of aerofoil with a truncated trailing edge. This is a novel method that contributes to an elevation of the serration technology to tackle multiple noise sources simultaneously. It was found that leading edge with a large serration amplitude and small serration wavelength represents an optimum choice. The work has been presented in the 25th AIAA/CEAS Aeroacoustics Conference in Delft, Netherlands in May 2019 DOI: 10.2514/6.2019-2437. A journal version of this work has been submitted to the Journal of Acoustical Society of America and is now published (doi:10.1121/10.0001377).

(5) The most significant key finding from this EPSRC "Quiet Aerofoil of the Next-Generation" project perhaps is the development of the Double-Rooted Trailing Edge Serration - tentatively, we call it DRooTES, as well as the slit trailing edge. These truly next-generation inventions can outperform the conventional serrated trailing edge designs in the followings: (1) Frequency targeting - a new landscape, where for the first time we can actually target/tune the frequency that we want to reduce, (2) The 1st generation serration is know to deteriorate in performance at high Reynolds number. However our DRooTES and Slit can continue to work very well at high Reynolds number, and (3) simple to manufacture - The manufacturing of this new design in industry is exactly the same as those currently adopted in the wind turbine industry, i.e. add-on type. Therefore it is readily to be implemented in the industry applications. A patent for the DRooTES (as well as the Slit), is now submitted in May 2020 (WO/2020/229829, A METHOD FOR FORMING AN ADD-ON COMPONENT FOR AN AEROFOIL). Further development of the DRooTES and slit concept is currently underway.
Exploitation Route We have actively engaged with our industrial project partners for this EPSRC project (Airbus aerospace and Vestas wind turbine) to disseminate key findings in this project. We will also explore the routes and steps that we should take in order to transfer the new technology developed in this project from the laboratory to a full scale prototype. Supported by the EPSRC Impact Acceleration Account (IAA) - Readiness, and collaborated with the Vestas Wind Turbine, validation of the serration performances at high Reynolds number has just been performed in the NWTF Anechoic Wind Tunnel, University of Southampton at February 2021 (it was originally scheduled in March 2020, but had to be cancelled due to the nationwide lockdown as a result of the COVID-19). The results will pave the way for enhanced industrial collaboration and accelerate the adoption of the next-generation technology in industrial blades.

The DRooTES and Slit are two very promising next-generation concepts in low-noise aerofoil and we will actively seek several avenues to further development after the conclusion of this EPSRC project, as well as to disseminate it as widely as possible to the academic and industrial research communities.
Sectors Aerospace, Defence and Marine,Education,Energy,Environment,Manufacturing, including Industrial Biotechology,Transport
URL http://researchfeatures.com/2017/11/02/new-generation-quiet-aerofoils/
 
Description This EPSRC project ended at May 2019. Some measurable impacts have already been registered. For example, we would like to draw attention to our active engagements at Brunel's STEM Center where the latest outcomes of this project are continuously disseminated to the school students by my research team members (PhD students, post-doc and myself). Most of the school students are fascinated by the idea of mimicking nature characteristics into engineering products to achieve better performances in aeroacoustics and aerodynamics. The feedback we received from schools is the increased environmental awareness from the students, and they generally become more aware of the importance of low-noise fan blades in the aviation and wind turbine sectors after attending Brunel's STEM activities. In 2018 my team and I participated in the "Made in Brunel" public showcase held at OXO Bargehouse to raise public awareness of the efforts from scientific community to reduce wind-turbine and aviation noises, and how bio-inspired concepts (e.g. serration from owls) can realise this ambitious goal. One notable example of positive impact is that we are able to prompt the general public to suggest the implementation of our low-noise technology derived from this project for the reduction of drone noise - something they perceive as the new threat for the urban acoustics. Frequent participations are conducted to breakdown the barriers between sciences and non-specialists through public engagement activities like disseminating research outcomes in the Research Feature Magazine. The project, which also collaborates with 3 other Universities (Southampton, Nottingham and City) and 2 industrial partners (Airbus and Vestas), has been shortlisted for The Engineer "Collaborate to Innovate" Awards 2018. As wind turbine blades move through the air, they produce noise. To protect residents, maximum noise levels are set that may not be exceeded. To stay within the noise limit, wind turbines often need to operate at reduced speed, which makes wind energy effectively more expensive. Reduction of noise without reducing the rotor speed would therefore make wind energy cheaper and, hence, a more attractive alternative for fossil energy. I have successfully obtained a direct investment from the Vestas Wind Turbine System A/S for a 3-year PhD studentship at Brunel to jointly-develop the next-generation low-noise wind turbine blades. Vestas is one of the top three producers of wind turbine blades in the world, and the collaboration with them is expected to accelerate the transfer from the laboratory mock-up to the real world engineering products. It is foreseeable that the collaboration will enhance the impacts on the economic, societal and policy making from the government. A new serration technology has been developed in this project. The "Double Rooted Trailing Edge Serrations", or DRooTES, could add an extra noise reduction mechanism (acoustic destructive interference) to the serration to achieve further level of noise reduction. This inventions of low-noise aerofoil resulted in a new patent application submitted on 11 September 2020 (A method for forming an add-on component for an aerofoil, WO/2020/229829). Overall, this EPSRC project (EP/N018737/1) has so far achieved very high number of outputs in journal and conference publications, encouraged further collaborations and partnerships, attracted further funding, and resulted in development of research tools, methods, database, models, and intellectual property. Efforts will continuously be invested to maximise the research impact in the many years to come.
First Year Of Impact 2018
Sector Aerospace, Defence and Marine,Education,Energy,Manufacturing, including Industrial Biotechology,Transport
Impact Types Societal,Economic,Policy & public services
 
Description Direct investment from Vestas Wind System A/S (PhD studentship) to develop the next-generation quiet wind turbines
Amount £52,445 (GBP)
Organisation Vestas Wind Systems A/S 
Sector Private
Country Denmark
Start 10/2017 
End 09/2020
 
Description EPSRC Impact Acceleration Account - Readiness (Validation of the Readiness of the Next-Generation Aerofoil at High Reynolds Numbers)
Amount £42,400 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 05/2018 
End 07/2021
 
Description Improving the industrial readiness for the Brunel invention of Double Rooted Trailing Edge Serrations (DRooTES) for aerofoil noise reduction
Amount £49,555 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2022 
End 04/2022
 
Description Innovate UK Innovation to commercialisation of university research (ICURe) on Poro-serrated fan blade trailing edges for reduced noise
Amount £35,000 (GBP)
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 04/2018 
End 07/2018
 
Description QUIET AEROFOIL WITH ADAPTIVE POROUS SURFACES (QUADPORS)
Amount £346,033 (GBP)
Funding ID EP/V006886/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2020 
End 03/2023
 
Title Design of a low-noise anechoic wind tunnel 
Description In order to validate the effectiveness of the plasma actuator in the reduction of aerofoil self-noise, as per the EPSRC project (EP/K002309/1), it is necessary to perform the experiment in a very low-noise aeroacoustics wind tunnel that cannot be bought "off the shelf". On a tight schedule and budget, I have designed, project managed and characterised a very unique anechoic wind tunnel facility at Brunel University that has become one of the only two available in the UK's universities - the other one is situated at the Institute of Sound and Vibration Research (ISVR), University of Southampton. Brunel's anechoic wind tunnel has been shown to produce very low background noise and low turbulence free jet and it is extremely versatile. It can support projects other than this particular EPSRC project (EP/K002309/1). For example, this wind tunnel continues to support my other EPSRC projects such as the EP/N018737/1 (completed) and EP/V006886/1 (ongoing). 
Type Of Material Improvements to research infrastructure 
Year Produced 2015 
Provided To Others? Yes  
Impact The anechoic wind tunnel developed here consists of an open jet wind tunnel situated inside an anechoic chamber. Some of the aeroacoustic research groups in the UK, as well as from overseas, are recently developing their aeroacoustic wind tunnel facilities largely based on this model. 
 
Title Generation of deterministic turbulent flow to study aerodynamic noise mechanisms in spatial and temporal domains 
Description The use of bio-inspired serration technology to reduce aerofoil trailing edge noise is a well-known method. However, the underlying mechanisms are still not understood well. This is due to the difficulty in mapping the unsteady nature of turbulent flow in both time and space when passing over the serration surface. To achieve this, it is often required the use of high fidelity experimental and numerical tools, e.g. time-resolved particle image velocimetry or direct numerical simulation. These are very expensive and are not easily accessible. The novelty of this doctoral research is that a pseudo-turbulent flow can be generated in a controlled manner near the trailing edge serration surface, whilst the spatial and temporal developments can be traced and studied by low-fidelity experimental technique such as the hot wire and low frequency response PIV system. The technique allows a detailed study of the mechanism of serration technology in the reduction of trailing edge self-noise. The technique can also be extended to other flow/acoustic studies, such as the laminar instability noise where the passing of synthetic turbulent flow is used as a re-setting mechanism for the aeroacoustics feedback loop structure. It can also be used to study other self-noise scenarios when the aerofoil trailing edge is subjected to different flow control treatments, such as the porous structure, surface texture, or finlet, whose mechanisms are largely not understood very well at present. Similarly, deterministic turbulence in free flow can also be generated by the active turbulence grid method. Applying the same principle of spatio-temporal capturing of the hydrodynamic field and acoustic far-field, the proposed technique can be extended to the turbulence-leading edge interaction noise. This work is now completed with a successful outcome. Dissemination of the research output based on this technique can be found at "Juknevicius, A and Chong T.P., (2021) The formation of the aeroacoustics feedback loop for a laminar aerofoil, AIAA Aviation 2021, AIAA-2021-2261, doi: 10.2514/6.2021-2261", and "Chong T.P. and Juknevicius, A. (2022) Reconstruction of the deterministic turbulent boundary layer for the study of aerofoil self-noise mechanisms, Experiments in Fluids, 63, 139. doi: 10.1007/s00348-022-03486-7". 
Type Of Material Improvements to research infrastructure 
Year Produced 2021 
Provided To Others? Yes  
Impact The expected impact of this research method is that we can now use low fidelity experimental tool, which is easily available, to study complex flow/acoustic problems. I will implement this method in my recently awarded EPSRC grant "QUADPORS EP/V006886/1". 
URL https://link.springer.com/article/10.1007/s00348-022-03486-7
 
Title Use of plasma actuators to generate various base-flow conditions 
Description A plasma actuator can be configured such that the travelling waves it generated can either enhance or deteriorate the flow. For all of the experiments carried out in the EP/K002309/1 project, the plasma actuators were optimised to the configurations such that they can suppress the wake vortex shedding and reduce the turbulence level of the boundary layer in order to produce a less-turbulent and steady flow. Measuring the flow separation noise is one of the main objectives for the current EP/N018737/1 project. To develop a "triggering" method for the boundary layer without subjecting it to large pressure loadings, we are developing a novel method to use the plasma actuator to produce an adverse flow (large scale boundary layer separation) in an otherwise laminar flow condition. This will enable us to study the leading edge and boundary layer separation noise without the need of extensive modification of the current wind tunnel facility. 
Type Of Material Improvements to research infrastructure 
Year Produced 2017 
Provided To Others? Yes  
Impact As stated in the "Collaborations and Partnerships" section, the limitation on performing aeroacoustic measurements on high angle of attack, and large pressure loadings for aerofoil by an open jet wind tunnel can be overcome by using the plasma actuator to generate a large scale boundary layer separation artificially. This advanced experimental technique would enable us to study and measure the flow separation noise - something that has hitherto not been investigated adequately in the research community due to limitation in the capability of the wind tunnel facility. 
 
Title Development of empirical model for aerofoil leading edge noise subjected to straight and curved serration 
Description From the EPSRC "Quiet Aerofoil of the Next Generation" project, my research team has acquired considerably amount of experimental data for the aerofoil noise radiation subjected to leading edge serration. 25 different combinations of the serration geometries were tested at a large range of velocity, and we are able to develop an empirical model to describe the level of noise reduction, as a function of scaled-frequency by the serration amplitude and serration wavelength, for both the straight and curved serration. This model will serve as a useful design criteria for low-noise fan blades. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact No notable impact has been recorded yet. 
URL https://www.sciencedirect.com/science/article/pii/S0022460X18301342
 
Title Statistical-empirical modeling of airfoil noise subjected to leading-edge serrations 
Description With the objective of reducing the broadband noise from the interaction of highly turbulent flow and airfoil leading edge, sinusoidal leading-edge serrations were investigated as an effective passive treatment. An extensive aeroacoustic study was performed to determine the main influences and interdependencies of factors, such as the Reynolds number, turbulence intensity, serration amplitude, and wavelength as well as the angle of attack on the noise reduction capability. A statistical-empirical model was developed to predict the overall sound pressure level and noise reduction of a NACA 65(12)-10 airfoil with and without leading-edge serrations in the range of chord-based Reynolds numbers of 2.5 × 10^5 = Re = 6 × 10^5. The observed main influencing factors on the noise radiation were quantified in a systematic order for the first time. Moreover, significant interdependencies of the turbulence intensity and the serration wavelength, as well as the serration wavelength and the angle of attack, were observed, validated, and quantified. The statistical-empirical model was validated against an external set of experimental data, which is shown to be accurate and reliable. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact High citation in the literatures (Scopus: 45 as of 15 Mar 2023). 
 
Description Aerofoil Trailing Edge Self-Noise Prediction and Reduction for the Next-Generation Wind Turbines at VESTAS 
Organisation Vestas Wind Systems A/S
Country Denmark 
Sector Private 
PI Contribution This collaboration concerns a 3-year PhD research programme funded by Vestas Wind Systems (50%), and the other 50% is funded by the EPSRC DTP (Doctoral Training Partnership). This industrial collaboration runs almost in parallel with my EPSRC grant on the "Quiet Aerofoils of the Next Generation EP/N018737/1", and has two major aims. First is to encourage new serration technologies that are developed in the EPSRC project to be easily transferred to Vestas in order to improve the Technological Readiness Level (TRL). The second aim is to develop next generation hybrid technology to wind turbine blade. To achieve the above aims, the following objectives have been established for our research team at Brunel: (1) improvement of the understandings of the noise reduction mechanism by a serrated trailing edge under different loading conditions, (2) understanding of the sensitivities of the serrated trailing edge with flap angles in noise and aerodynamic performances, (3) appreciation of the effect of small changes in geometries parameters and aerofoil geometry, (4) development of the novel and innovative serration designs, (5) and most importantly, to combine the serration technology with another passive control device to form a hybrid device in order to harness extra benefits for noise reduction. Vestas is also one of our industrial collaborators for another EPSRC project EP/V006886/1 - Quiet Aerofoil with Adaptive Porous Surface (QUADPORS), which is still ongoing. In this project, we are developing the adaptive porous trailing edge for self-noise reduction. In this project, we have developed a new concept - "Selective Interference Mono-Porous Line trailing Edge - SIMPLE" which has frequency tuning capability, credential at high Reynolds number and minimal aerodynamic penalties. This concept has attracted attention from Vestas, who has expressed interest to fund further development of this concept after the QUADPORS project.
Collaborator Contribution Vestas supports the research programme by participating in bi-weekly review meeting, providing comments/feedbacks from the industrial perspective and facilitating on-field aeroacoustics tests of a real-size wind turbine in one of their test facility.
Impact The PhD student who worked in this project commenced at October 2017, and completed all the experiments in December 2020. The major contribution of this work is the development of a novel hybrid device that contains serration and surface treatment technology (Finlet) for a much improved aeroacoustics performance for aerofoil. This particular research output has been first disseminated in the "Schroeder, E., Chong, T. P., Kamruzzaman, M., Hurault, J., & Joseph, P. (2019). Aerofoil trailing edge self-noise reduction by Surface Mounted Attenuation Devices. In Proceedings of the International Congress on Acoustics Vol. 2019-September (pp. 5327-5334). doi:10.18154/RWTH-CONV-240018." Following this, we have uncovered a novel way to maximise the serration and Finlet to achieve an even greater level of noise reduction. Full results have been documented in the "Jung-Hoon Kim, Max M. Scholz, Tze Pei Chong, Phillip Joseph and Tomas Vronsky. (2022). Executing the Source-Radiation Targeting on Aerofoil Trailing Edge Noise by the Finlet-Serration. In Proceedings of the 28th AIAA/CEAS Aeroacoustics Conference, Southampton, UK. doi: 10.2514/6.2022-3104". It is expected that Vestas will absorb this technology to further improve its readiness level and eventually adapt it to their wind turbine to achieve noise reduction.
Start Year 2017
 
Description National and international academic collaborations 
Organisation City, University of London
Country United Kingdom 
Sector Academic/University 
PI Contribution I have successfully developed a state-of-the-art plasma actuator system at the conclusion of my EPSRC First Grant (EP/K002309/1), which is to use the plasma actuators as an active flow control device to reduce aerofoil broadband and tonal noise produced at the trailing edge of aerofoil. To move this technology forward, I have partnered with several world-leading experts in flow control and aeroacoustics to develop a multi-disciplinary approach (combined active and passive flow controls) to reduce the industrial fan noise and improve the aerodynamic performances, which is closely associated with the EPSRC project (EP/N018737/1 - Quiet aerofoil of the next generation, 30 Apr 2016 - 31 May 2019) where I was one of the principle investigators. Whilst my main area of research in this project is to improve the serration technology (a passive flow control) to improve the aerodynamic and aeroacoustics performances of aerofoil, I also develop a hybrid system to combine the plasma actuators with the serration and riblets to develop the next generation industrial fan blades. The plasma actuator aeroacoustics control research is further enhanced with my collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India (https://home.iitm.ac.in/nrv/), who has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. I have recruited a new PhD student to work on the plasma actuator for aeroacoustics control. The numerical work from Professor Vadlamani will complement our experimental work to help in the explanation of the flow physical behaviours. I have been collaborating with University of Southampton, University of Nottingham and City University of London on two EPSRC projects (1) EP/N018737/1 - Quiet aerofoil of the next generation - completed; and (2) EP/V006886/1 - Quiet Aerofoil with Adaptive Porous Surfaces (QUADPORS) - ongoing. Detailed contributions of my research team at Brunel for these two projects have been documented elsewhere within the Researchfish.
Collaborator Contribution Professor Phillip Joseph (ISVR, University of Southampton) is a world-leading expert and he will be developing the serration/geometrical modification techniques to achieve quiet aerofoil. Professor Kwing-So Choi from the University of Nottingham is to develop the bio-inspired, surface riblet technique to reduce the skin friction drag. Professor Alfredo Pinelli from City University London contributes towards high fidelity simulation on fluid flows, whose results are transferrable to the aeroacoustics scatered fields. Dr Oksana Stalnov is an assistant professor at Technion Israel Institute of Technology and she is responsible to develop wall-blowing/mass-injection techniques, as well as the serration technology, to reduce the aerofoil self-noise radiation. Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India, has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. Professor Minghui Zhang from Shandong University of Science and Technology visited my research group for a year between 2019 and 2020. During this period, Professor Zhang worked on the structured porous trailing edge for aerofoil trailing edge noise reduction and we have produced two journal articles and a conference paper, all of which have already been published. My collaboration with Professor Zhang is an incubator for the development of a novel concept for quiet aerofoil, i.e. structured porous trailing edge, for further exploitation in my current EPSRC project (QUADPORS EP/V006886/1).
Impact Dr Oksana Stalnov and I have obtained some results on the hybrid leading edge serration and plasma actuator on the reduction of aerofoil turbulence-leading edge interaction noise. This concept has been extended to the use of hybrid serration and active air-blowing through mechanical means, in which the results have been published in "Yasir Al-Okbi, Tze Pei Chong and Oksana Stalnov, Leading Edge Blowing to Mimic and Enhance the Serration Effects for Aerofoil. Applied Sciences, 11(6), 2593. doi:10.3390/app11062593". We are also working together to explore the scaling effect of aerofoil lift coefficients subjected to leading edge serrations, in which a journal article is published in "Stalnov, O., & Chong, T. P. (2019). Scaling of Lift Coefficient of an Airfoil with Leading Edge Serrations. AIAA Journal, 57(8), 3615-3619. doi:10.2514/1.J058168". Apart from working closely together with Professor Phillip Joseph, Professor Kwing-So Choi and Professor Alfredo Pinelli on the work packages defined in the EP/N018737/1 and EP/V006886/1, we are also developing the plasma actuator as an effective non-intrusive device to artificially trigger a large scale flow separation on fan blade surface at low angle of attack, and low pressure loadings. The motivation of this research is to overcome the limitation on performing aeroacoustics measurements of aerofoil subjected to high angle of attack, and large pressure loadings by most of the open jet wind tunnel. The success of this advanced experimental technique would enable us we to continuously use our current open jet aeroacoustics facility to measure the flow separation noise. The flow separation noise is one of the prominent engineering problems facing the industrial fan blades, but it has hitherto not been investigated adequately in the research community and there is a lack of database in the literatures. This particular research work (i.e. use the plasma actuator to generate adverse flow condition - boundary layer separation) has encountered some "self-noise" issues from the plasma actuators which tend to mask the aerodynamic noise of interest. This has been mitigated by investigating at a high velocity flow condition so that the plasma actuator self-noise will be less significant. Professor Joseph, Professor Choi, Professor Pinelli and I will continue to collaborate in this topic alongside the current EPSRC QUADPORS project (EP/V006886/1). The collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras has started at February 2021. Although encountered a slow start initially due to some numerical issues, most of which have been overcome and preliminary results start to emerge. In the near future, we will validate the numerical results with our experimental data. The research outcomes will be disseminated in the conference proceedings and journal articles in near future. The collaboration with Professor Minghui Zhang produces two journal articles and one conference proceedings. The know-how and experiences gained in the project are transferable to my current EPSRC project "QUADPORS - EP/V006886/1".
Start Year 2016
 
Description National and international academic collaborations 
Organisation Indian Institute of Technology Madras
Country India 
Sector Academic/University 
PI Contribution I have successfully developed a state-of-the-art plasma actuator system at the conclusion of my EPSRC First Grant (EP/K002309/1), which is to use the plasma actuators as an active flow control device to reduce aerofoil broadband and tonal noise produced at the trailing edge of aerofoil. To move this technology forward, I have partnered with several world-leading experts in flow control and aeroacoustics to develop a multi-disciplinary approach (combined active and passive flow controls) to reduce the industrial fan noise and improve the aerodynamic performances, which is closely associated with the EPSRC project (EP/N018737/1 - Quiet aerofoil of the next generation, 30 Apr 2016 - 31 May 2019) where I was one of the principle investigators. Whilst my main area of research in this project is to improve the serration technology (a passive flow control) to improve the aerodynamic and aeroacoustics performances of aerofoil, I also develop a hybrid system to combine the plasma actuators with the serration and riblets to develop the next generation industrial fan blades. The plasma actuator aeroacoustics control research is further enhanced with my collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India (https://home.iitm.ac.in/nrv/), who has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. I have recruited a new PhD student to work on the plasma actuator for aeroacoustics control. The numerical work from Professor Vadlamani will complement our experimental work to help in the explanation of the flow physical behaviours. I have been collaborating with University of Southampton, University of Nottingham and City University of London on two EPSRC projects (1) EP/N018737/1 - Quiet aerofoil of the next generation - completed; and (2) EP/V006886/1 - Quiet Aerofoil with Adaptive Porous Surfaces (QUADPORS) - ongoing. Detailed contributions of my research team at Brunel for these two projects have been documented elsewhere within the Researchfish.
Collaborator Contribution Professor Phillip Joseph (ISVR, University of Southampton) is a world-leading expert and he will be developing the serration/geometrical modification techniques to achieve quiet aerofoil. Professor Kwing-So Choi from the University of Nottingham is to develop the bio-inspired, surface riblet technique to reduce the skin friction drag. Professor Alfredo Pinelli from City University London contributes towards high fidelity simulation on fluid flows, whose results are transferrable to the aeroacoustics scatered fields. Dr Oksana Stalnov is an assistant professor at Technion Israel Institute of Technology and she is responsible to develop wall-blowing/mass-injection techniques, as well as the serration technology, to reduce the aerofoil self-noise radiation. Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India, has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. Professor Minghui Zhang from Shandong University of Science and Technology visited my research group for a year between 2019 and 2020. During this period, Professor Zhang worked on the structured porous trailing edge for aerofoil trailing edge noise reduction and we have produced two journal articles and a conference paper, all of which have already been published. My collaboration with Professor Zhang is an incubator for the development of a novel concept for quiet aerofoil, i.e. structured porous trailing edge, for further exploitation in my current EPSRC project (QUADPORS EP/V006886/1).
Impact Dr Oksana Stalnov and I have obtained some results on the hybrid leading edge serration and plasma actuator on the reduction of aerofoil turbulence-leading edge interaction noise. This concept has been extended to the use of hybrid serration and active air-blowing through mechanical means, in which the results have been published in "Yasir Al-Okbi, Tze Pei Chong and Oksana Stalnov, Leading Edge Blowing to Mimic and Enhance the Serration Effects for Aerofoil. Applied Sciences, 11(6), 2593. doi:10.3390/app11062593". We are also working together to explore the scaling effect of aerofoil lift coefficients subjected to leading edge serrations, in which a journal article is published in "Stalnov, O., & Chong, T. P. (2019). Scaling of Lift Coefficient of an Airfoil with Leading Edge Serrations. AIAA Journal, 57(8), 3615-3619. doi:10.2514/1.J058168". Apart from working closely together with Professor Phillip Joseph, Professor Kwing-So Choi and Professor Alfredo Pinelli on the work packages defined in the EP/N018737/1 and EP/V006886/1, we are also developing the plasma actuator as an effective non-intrusive device to artificially trigger a large scale flow separation on fan blade surface at low angle of attack, and low pressure loadings. The motivation of this research is to overcome the limitation on performing aeroacoustics measurements of aerofoil subjected to high angle of attack, and large pressure loadings by most of the open jet wind tunnel. The success of this advanced experimental technique would enable us we to continuously use our current open jet aeroacoustics facility to measure the flow separation noise. The flow separation noise is one of the prominent engineering problems facing the industrial fan blades, but it has hitherto not been investigated adequately in the research community and there is a lack of database in the literatures. This particular research work (i.e. use the plasma actuator to generate adverse flow condition - boundary layer separation) has encountered some "self-noise" issues from the plasma actuators which tend to mask the aerodynamic noise of interest. This has been mitigated by investigating at a high velocity flow condition so that the plasma actuator self-noise will be less significant. Professor Joseph, Professor Choi, Professor Pinelli and I will continue to collaborate in this topic alongside the current EPSRC QUADPORS project (EP/V006886/1). The collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras has started at February 2021. Although encountered a slow start initially due to some numerical issues, most of which have been overcome and preliminary results start to emerge. In the near future, we will validate the numerical results with our experimental data. The research outcomes will be disseminated in the conference proceedings and journal articles in near future. The collaboration with Professor Minghui Zhang produces two journal articles and one conference proceedings. The know-how and experiences gained in the project are transferable to my current EPSRC project "QUADPORS - EP/V006886/1".
Start Year 2016
 
Description National and international academic collaborations 
Organisation Shandong University of Science and Technology
Country China 
Sector Academic/University 
PI Contribution I have successfully developed a state-of-the-art plasma actuator system at the conclusion of my EPSRC First Grant (EP/K002309/1), which is to use the plasma actuators as an active flow control device to reduce aerofoil broadband and tonal noise produced at the trailing edge of aerofoil. To move this technology forward, I have partnered with several world-leading experts in flow control and aeroacoustics to develop a multi-disciplinary approach (combined active and passive flow controls) to reduce the industrial fan noise and improve the aerodynamic performances, which is closely associated with the EPSRC project (EP/N018737/1 - Quiet aerofoil of the next generation, 30 Apr 2016 - 31 May 2019) where I was one of the principle investigators. Whilst my main area of research in this project is to improve the serration technology (a passive flow control) to improve the aerodynamic and aeroacoustics performances of aerofoil, I also develop a hybrid system to combine the plasma actuators with the serration and riblets to develop the next generation industrial fan blades. The plasma actuator aeroacoustics control research is further enhanced with my collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India (https://home.iitm.ac.in/nrv/), who has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. I have recruited a new PhD student to work on the plasma actuator for aeroacoustics control. The numerical work from Professor Vadlamani will complement our experimental work to help in the explanation of the flow physical behaviours. I have been collaborating with University of Southampton, University of Nottingham and City University of London on two EPSRC projects (1) EP/N018737/1 - Quiet aerofoil of the next generation - completed; and (2) EP/V006886/1 - Quiet Aerofoil with Adaptive Porous Surfaces (QUADPORS) - ongoing. Detailed contributions of my research team at Brunel for these two projects have been documented elsewhere within the Researchfish.
Collaborator Contribution Professor Phillip Joseph (ISVR, University of Southampton) is a world-leading expert and he will be developing the serration/geometrical modification techniques to achieve quiet aerofoil. Professor Kwing-So Choi from the University of Nottingham is to develop the bio-inspired, surface riblet technique to reduce the skin friction drag. Professor Alfredo Pinelli from City University London contributes towards high fidelity simulation on fluid flows, whose results are transferrable to the aeroacoustics scatered fields. Dr Oksana Stalnov is an assistant professor at Technion Israel Institute of Technology and she is responsible to develop wall-blowing/mass-injection techniques, as well as the serration technology, to reduce the aerofoil self-noise radiation. Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India, has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. Professor Minghui Zhang from Shandong University of Science and Technology visited my research group for a year between 2019 and 2020. During this period, Professor Zhang worked on the structured porous trailing edge for aerofoil trailing edge noise reduction and we have produced two journal articles and a conference paper, all of which have already been published. My collaboration with Professor Zhang is an incubator for the development of a novel concept for quiet aerofoil, i.e. structured porous trailing edge, for further exploitation in my current EPSRC project (QUADPORS EP/V006886/1).
Impact Dr Oksana Stalnov and I have obtained some results on the hybrid leading edge serration and plasma actuator on the reduction of aerofoil turbulence-leading edge interaction noise. This concept has been extended to the use of hybrid serration and active air-blowing through mechanical means, in which the results have been published in "Yasir Al-Okbi, Tze Pei Chong and Oksana Stalnov, Leading Edge Blowing to Mimic and Enhance the Serration Effects for Aerofoil. Applied Sciences, 11(6), 2593. doi:10.3390/app11062593". We are also working together to explore the scaling effect of aerofoil lift coefficients subjected to leading edge serrations, in which a journal article is published in "Stalnov, O., & Chong, T. P. (2019). Scaling of Lift Coefficient of an Airfoil with Leading Edge Serrations. AIAA Journal, 57(8), 3615-3619. doi:10.2514/1.J058168". Apart from working closely together with Professor Phillip Joseph, Professor Kwing-So Choi and Professor Alfredo Pinelli on the work packages defined in the EP/N018737/1 and EP/V006886/1, we are also developing the plasma actuator as an effective non-intrusive device to artificially trigger a large scale flow separation on fan blade surface at low angle of attack, and low pressure loadings. The motivation of this research is to overcome the limitation on performing aeroacoustics measurements of aerofoil subjected to high angle of attack, and large pressure loadings by most of the open jet wind tunnel. The success of this advanced experimental technique would enable us we to continuously use our current open jet aeroacoustics facility to measure the flow separation noise. The flow separation noise is one of the prominent engineering problems facing the industrial fan blades, but it has hitherto not been investigated adequately in the research community and there is a lack of database in the literatures. This particular research work (i.e. use the plasma actuator to generate adverse flow condition - boundary layer separation) has encountered some "self-noise" issues from the plasma actuators which tend to mask the aerodynamic noise of interest. This has been mitigated by investigating at a high velocity flow condition so that the plasma actuator self-noise will be less significant. Professor Joseph, Professor Choi, Professor Pinelli and I will continue to collaborate in this topic alongside the current EPSRC QUADPORS project (EP/V006886/1). The collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras has started at February 2021. Although encountered a slow start initially due to some numerical issues, most of which have been overcome and preliminary results start to emerge. In the near future, we will validate the numerical results with our experimental data. The research outcomes will be disseminated in the conference proceedings and journal articles in near future. The collaboration with Professor Minghui Zhang produces two journal articles and one conference proceedings. The know-how and experiences gained in the project are transferable to my current EPSRC project "QUADPORS - EP/V006886/1".
Start Year 2016
 
Description National and international academic collaborations 
Organisation Technion - Israel Institute of Technology
Country Israel 
Sector Academic/University 
PI Contribution I have successfully developed a state-of-the-art plasma actuator system at the conclusion of my EPSRC First Grant (EP/K002309/1), which is to use the plasma actuators as an active flow control device to reduce aerofoil broadband and tonal noise produced at the trailing edge of aerofoil. To move this technology forward, I have partnered with several world-leading experts in flow control and aeroacoustics to develop a multi-disciplinary approach (combined active and passive flow controls) to reduce the industrial fan noise and improve the aerodynamic performances, which is closely associated with the EPSRC project (EP/N018737/1 - Quiet aerofoil of the next generation, 30 Apr 2016 - 31 May 2019) where I was one of the principle investigators. Whilst my main area of research in this project is to improve the serration technology (a passive flow control) to improve the aerodynamic and aeroacoustics performances of aerofoil, I also develop a hybrid system to combine the plasma actuators with the serration and riblets to develop the next generation industrial fan blades. The plasma actuator aeroacoustics control research is further enhanced with my collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India (https://home.iitm.ac.in/nrv/), who has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. I have recruited a new PhD student to work on the plasma actuator for aeroacoustics control. The numerical work from Professor Vadlamani will complement our experimental work to help in the explanation of the flow physical behaviours. I have been collaborating with University of Southampton, University of Nottingham and City University of London on two EPSRC projects (1) EP/N018737/1 - Quiet aerofoil of the next generation - completed; and (2) EP/V006886/1 - Quiet Aerofoil with Adaptive Porous Surfaces (QUADPORS) - ongoing. Detailed contributions of my research team at Brunel for these two projects have been documented elsewhere within the Researchfish.
Collaborator Contribution Professor Phillip Joseph (ISVR, University of Southampton) is a world-leading expert and he will be developing the serration/geometrical modification techniques to achieve quiet aerofoil. Professor Kwing-So Choi from the University of Nottingham is to develop the bio-inspired, surface riblet technique to reduce the skin friction drag. Professor Alfredo Pinelli from City University London contributes towards high fidelity simulation on fluid flows, whose results are transferrable to the aeroacoustics scatered fields. Dr Oksana Stalnov is an assistant professor at Technion Israel Institute of Technology and she is responsible to develop wall-blowing/mass-injection techniques, as well as the serration technology, to reduce the aerofoil self-noise radiation. Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India, has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. Professor Minghui Zhang from Shandong University of Science and Technology visited my research group for a year between 2019 and 2020. During this period, Professor Zhang worked on the structured porous trailing edge for aerofoil trailing edge noise reduction and we have produced two journal articles and a conference paper, all of which have already been published. My collaboration with Professor Zhang is an incubator for the development of a novel concept for quiet aerofoil, i.e. structured porous trailing edge, for further exploitation in my current EPSRC project (QUADPORS EP/V006886/1).
Impact Dr Oksana Stalnov and I have obtained some results on the hybrid leading edge serration and plasma actuator on the reduction of aerofoil turbulence-leading edge interaction noise. This concept has been extended to the use of hybrid serration and active air-blowing through mechanical means, in which the results have been published in "Yasir Al-Okbi, Tze Pei Chong and Oksana Stalnov, Leading Edge Blowing to Mimic and Enhance the Serration Effects for Aerofoil. Applied Sciences, 11(6), 2593. doi:10.3390/app11062593". We are also working together to explore the scaling effect of aerofoil lift coefficients subjected to leading edge serrations, in which a journal article is published in "Stalnov, O., & Chong, T. P. (2019). Scaling of Lift Coefficient of an Airfoil with Leading Edge Serrations. AIAA Journal, 57(8), 3615-3619. doi:10.2514/1.J058168". Apart from working closely together with Professor Phillip Joseph, Professor Kwing-So Choi and Professor Alfredo Pinelli on the work packages defined in the EP/N018737/1 and EP/V006886/1, we are also developing the plasma actuator as an effective non-intrusive device to artificially trigger a large scale flow separation on fan blade surface at low angle of attack, and low pressure loadings. The motivation of this research is to overcome the limitation on performing aeroacoustics measurements of aerofoil subjected to high angle of attack, and large pressure loadings by most of the open jet wind tunnel. The success of this advanced experimental technique would enable us we to continuously use our current open jet aeroacoustics facility to measure the flow separation noise. The flow separation noise is one of the prominent engineering problems facing the industrial fan blades, but it has hitherto not been investigated adequately in the research community and there is a lack of database in the literatures. This particular research work (i.e. use the plasma actuator to generate adverse flow condition - boundary layer separation) has encountered some "self-noise" issues from the plasma actuators which tend to mask the aerodynamic noise of interest. This has been mitigated by investigating at a high velocity flow condition so that the plasma actuator self-noise will be less significant. Professor Joseph, Professor Choi, Professor Pinelli and I will continue to collaborate in this topic alongside the current EPSRC QUADPORS project (EP/V006886/1). The collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras has started at February 2021. Although encountered a slow start initially due to some numerical issues, most of which have been overcome and preliminary results start to emerge. In the near future, we will validate the numerical results with our experimental data. The research outcomes will be disseminated in the conference proceedings and journal articles in near future. The collaboration with Professor Minghui Zhang produces two journal articles and one conference proceedings. The know-how and experiences gained in the project are transferable to my current EPSRC project "QUADPORS - EP/V006886/1".
Start Year 2016
 
Description National and international academic collaborations 
Organisation University of Nottingham
Department Faculty of Engineering
Country United Kingdom 
Sector Academic/University 
PI Contribution I have successfully developed a state-of-the-art plasma actuator system at the conclusion of my EPSRC First Grant (EP/K002309/1), which is to use the plasma actuators as an active flow control device to reduce aerofoil broadband and tonal noise produced at the trailing edge of aerofoil. To move this technology forward, I have partnered with several world-leading experts in flow control and aeroacoustics to develop a multi-disciplinary approach (combined active and passive flow controls) to reduce the industrial fan noise and improve the aerodynamic performances, which is closely associated with the EPSRC project (EP/N018737/1 - Quiet aerofoil of the next generation, 30 Apr 2016 - 31 May 2019) where I was one of the principle investigators. Whilst my main area of research in this project is to improve the serration technology (a passive flow control) to improve the aerodynamic and aeroacoustics performances of aerofoil, I also develop a hybrid system to combine the plasma actuators with the serration and riblets to develop the next generation industrial fan blades. The plasma actuator aeroacoustics control research is further enhanced with my collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India (https://home.iitm.ac.in/nrv/), who has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. I have recruited a new PhD student to work on the plasma actuator for aeroacoustics control. The numerical work from Professor Vadlamani will complement our experimental work to help in the explanation of the flow physical behaviours. I have been collaborating with University of Southampton, University of Nottingham and City University of London on two EPSRC projects (1) EP/N018737/1 - Quiet aerofoil of the next generation - completed; and (2) EP/V006886/1 - Quiet Aerofoil with Adaptive Porous Surfaces (QUADPORS) - ongoing. Detailed contributions of my research team at Brunel for these two projects have been documented elsewhere within the Researchfish.
Collaborator Contribution Professor Phillip Joseph (ISVR, University of Southampton) is a world-leading expert and he will be developing the serration/geometrical modification techniques to achieve quiet aerofoil. Professor Kwing-So Choi from the University of Nottingham is to develop the bio-inspired, surface riblet technique to reduce the skin friction drag. Professor Alfredo Pinelli from City University London contributes towards high fidelity simulation on fluid flows, whose results are transferrable to the aeroacoustics scatered fields. Dr Oksana Stalnov is an assistant professor at Technion Israel Institute of Technology and she is responsible to develop wall-blowing/mass-injection techniques, as well as the serration technology, to reduce the aerofoil self-noise radiation. Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India, has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. Professor Minghui Zhang from Shandong University of Science and Technology visited my research group for a year between 2019 and 2020. During this period, Professor Zhang worked on the structured porous trailing edge for aerofoil trailing edge noise reduction and we have produced two journal articles and a conference paper, all of which have already been published. My collaboration with Professor Zhang is an incubator for the development of a novel concept for quiet aerofoil, i.e. structured porous trailing edge, for further exploitation in my current EPSRC project (QUADPORS EP/V006886/1).
Impact Dr Oksana Stalnov and I have obtained some results on the hybrid leading edge serration and plasma actuator on the reduction of aerofoil turbulence-leading edge interaction noise. This concept has been extended to the use of hybrid serration and active air-blowing through mechanical means, in which the results have been published in "Yasir Al-Okbi, Tze Pei Chong and Oksana Stalnov, Leading Edge Blowing to Mimic and Enhance the Serration Effects for Aerofoil. Applied Sciences, 11(6), 2593. doi:10.3390/app11062593". We are also working together to explore the scaling effect of aerofoil lift coefficients subjected to leading edge serrations, in which a journal article is published in "Stalnov, O., & Chong, T. P. (2019). Scaling of Lift Coefficient of an Airfoil with Leading Edge Serrations. AIAA Journal, 57(8), 3615-3619. doi:10.2514/1.J058168". Apart from working closely together with Professor Phillip Joseph, Professor Kwing-So Choi and Professor Alfredo Pinelli on the work packages defined in the EP/N018737/1 and EP/V006886/1, we are also developing the plasma actuator as an effective non-intrusive device to artificially trigger a large scale flow separation on fan blade surface at low angle of attack, and low pressure loadings. The motivation of this research is to overcome the limitation on performing aeroacoustics measurements of aerofoil subjected to high angle of attack, and large pressure loadings by most of the open jet wind tunnel. The success of this advanced experimental technique would enable us we to continuously use our current open jet aeroacoustics facility to measure the flow separation noise. The flow separation noise is one of the prominent engineering problems facing the industrial fan blades, but it has hitherto not been investigated adequately in the research community and there is a lack of database in the literatures. This particular research work (i.e. use the plasma actuator to generate adverse flow condition - boundary layer separation) has encountered some "self-noise" issues from the plasma actuators which tend to mask the aerodynamic noise of interest. This has been mitigated by investigating at a high velocity flow condition so that the plasma actuator self-noise will be less significant. Professor Joseph, Professor Choi, Professor Pinelli and I will continue to collaborate in this topic alongside the current EPSRC QUADPORS project (EP/V006886/1). The collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras has started at February 2021. Although encountered a slow start initially due to some numerical issues, most of which have been overcome and preliminary results start to emerge. In the near future, we will validate the numerical results with our experimental data. The research outcomes will be disseminated in the conference proceedings and journal articles in near future. The collaboration with Professor Minghui Zhang produces two journal articles and one conference proceedings. The know-how and experiences gained in the project are transferable to my current EPSRC project "QUADPORS - EP/V006886/1".
Start Year 2016
 
Description National and international academic collaborations 
Organisation University of Southampton
Country United Kingdom 
Sector Academic/University 
PI Contribution I have successfully developed a state-of-the-art plasma actuator system at the conclusion of my EPSRC First Grant (EP/K002309/1), which is to use the plasma actuators as an active flow control device to reduce aerofoil broadband and tonal noise produced at the trailing edge of aerofoil. To move this technology forward, I have partnered with several world-leading experts in flow control and aeroacoustics to develop a multi-disciplinary approach (combined active and passive flow controls) to reduce the industrial fan noise and improve the aerodynamic performances, which is closely associated with the EPSRC project (EP/N018737/1 - Quiet aerofoil of the next generation, 30 Apr 2016 - 31 May 2019) where I was one of the principle investigators. Whilst my main area of research in this project is to improve the serration technology (a passive flow control) to improve the aerodynamic and aeroacoustics performances of aerofoil, I also develop a hybrid system to combine the plasma actuators with the serration and riblets to develop the next generation industrial fan blades. The plasma actuator aeroacoustics control research is further enhanced with my collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India (https://home.iitm.ac.in/nrv/), who has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. I have recruited a new PhD student to work on the plasma actuator for aeroacoustics control. The numerical work from Professor Vadlamani will complement our experimental work to help in the explanation of the flow physical behaviours. I have been collaborating with University of Southampton, University of Nottingham and City University of London on two EPSRC projects (1) EP/N018737/1 - Quiet aerofoil of the next generation - completed; and (2) EP/V006886/1 - Quiet Aerofoil with Adaptive Porous Surfaces (QUADPORS) - ongoing. Detailed contributions of my research team at Brunel for these two projects have been documented elsewhere within the Researchfish.
Collaborator Contribution Professor Phillip Joseph (ISVR, University of Southampton) is a world-leading expert and he will be developing the serration/geometrical modification techniques to achieve quiet aerofoil. Professor Kwing-So Choi from the University of Nottingham is to develop the bio-inspired, surface riblet technique to reduce the skin friction drag. Professor Alfredo Pinelli from City University London contributes towards high fidelity simulation on fluid flows, whose results are transferrable to the aeroacoustics scatered fields. Dr Oksana Stalnov is an assistant professor at Technion Israel Institute of Technology and she is responsible to develop wall-blowing/mass-injection techniques, as well as the serration technology, to reduce the aerofoil self-noise radiation. Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras, India, has a proven research track record in high fidelity LES/DNS to study active flow control of turbomachinery flow by plasma actuator. Professor Minghui Zhang from Shandong University of Science and Technology visited my research group for a year between 2019 and 2020. During this period, Professor Zhang worked on the structured porous trailing edge for aerofoil trailing edge noise reduction and we have produced two journal articles and a conference paper, all of which have already been published. My collaboration with Professor Zhang is an incubator for the development of a novel concept for quiet aerofoil, i.e. structured porous trailing edge, for further exploitation in my current EPSRC project (QUADPORS EP/V006886/1).
Impact Dr Oksana Stalnov and I have obtained some results on the hybrid leading edge serration and plasma actuator on the reduction of aerofoil turbulence-leading edge interaction noise. This concept has been extended to the use of hybrid serration and active air-blowing through mechanical means, in which the results have been published in "Yasir Al-Okbi, Tze Pei Chong and Oksana Stalnov, Leading Edge Blowing to Mimic and Enhance the Serration Effects for Aerofoil. Applied Sciences, 11(6), 2593. doi:10.3390/app11062593". We are also working together to explore the scaling effect of aerofoil lift coefficients subjected to leading edge serrations, in which a journal article is published in "Stalnov, O., & Chong, T. P. (2019). Scaling of Lift Coefficient of an Airfoil with Leading Edge Serrations. AIAA Journal, 57(8), 3615-3619. doi:10.2514/1.J058168". Apart from working closely together with Professor Phillip Joseph, Professor Kwing-So Choi and Professor Alfredo Pinelli on the work packages defined in the EP/N018737/1 and EP/V006886/1, we are also developing the plasma actuator as an effective non-intrusive device to artificially trigger a large scale flow separation on fan blade surface at low angle of attack, and low pressure loadings. The motivation of this research is to overcome the limitation on performing aeroacoustics measurements of aerofoil subjected to high angle of attack, and large pressure loadings by most of the open jet wind tunnel. The success of this advanced experimental technique would enable us we to continuously use our current open jet aeroacoustics facility to measure the flow separation noise. The flow separation noise is one of the prominent engineering problems facing the industrial fan blades, but it has hitherto not been investigated adequately in the research community and there is a lack of database in the literatures. This particular research work (i.e. use the plasma actuator to generate adverse flow condition - boundary layer separation) has encountered some "self-noise" issues from the plasma actuators which tend to mask the aerodynamic noise of interest. This has been mitigated by investigating at a high velocity flow condition so that the plasma actuator self-noise will be less significant. Professor Joseph, Professor Choi, Professor Pinelli and I will continue to collaborate in this topic alongside the current EPSRC QUADPORS project (EP/V006886/1). The collaboration with Professor Nagabhushana Rao Vadlamani from the Indian Institute of Technology Madras has started at February 2021. Although encountered a slow start initially due to some numerical issues, most of which have been overcome and preliminary results start to emerge. In the near future, we will validate the numerical results with our experimental data. The research outcomes will be disseminated in the conference proceedings and journal articles in near future. The collaboration with Professor Minghui Zhang produces two journal articles and one conference proceedings. The know-how and experiences gained in the project are transferable to my current EPSRC project "QUADPORS - EP/V006886/1".
Start Year 2016
 
Description Transfer of leading edge serration technology from the isolated aerofoil to ducted low-pressure industrial fan 
Organisation University of Applied Sciences Düsseldorf (HSD)
Country Germany 
Sector Academic/University 
PI Contribution Following the award of the EPSRC grant "Quiet Aerofoil of the Next Generation EP/N018737/1", it becomes apparent to me that it is necessary to be able to transfer the low-noise technology developed in the laboratory to the real-world industrial fan blades. The collaboration with Professor Frank Kameier and Dr Till Biedermann from University of Applied Sciences Duesseldorf, Germany, represents a good opportunity not only to improve the technological readiness level of our low-noise aerofoil technologies which are developed in-house, underpinned by advanced manufacturing techniques that have a real prospect to be adopted by industries, but also allows us to step into a niche area that has a large yield potential. My research team at Brunel is responsible for the acquisition and interpretation of the noise and flow data for an isolated, serrated-aerofoil. The understanding of the physical mechanism of noise sources and their suppression mechanisms by serration is then transferred to my partner in Germany so that the serrated-aerofoil can be further developed and implemented in the ducted low-pressure industrial fan. In 2019, I have been named as the visiting researcher for Dr Till Biedermann's successful grant application on the prestigious German Research Foundation, DFG, on the project to implement leading edge serration technology to industrial fan blades.
Collaborator Contribution Professor Frank Kameier and Dr Till Biedermann are both famous experts in the aerodynamic and aeroacoustics optimisation of industrial fan blades. Their expertise in this area greatly facilitates the transfer of superior aeroacoustics and aerodynamic performance parameters from an isolated aerofoil to ducted low-pressure industrial fan. They also let us to test our models in their ISO-standard aeroacoustics ducted fan rig for free.
Impact Dr Biedermann has successfully defended his PhD thesis, which is downloadable in https://depositonce.tu-berlin.de/handle/11303/10084 . The thesis is built upon the transfer of some of the 2D aerofoil results obtained in my EPSRC grant "Quiet Aerofoil of the Next Generation EP/N018737/1" to 3D propellers, which is conducted in the University of Applied Sciences Duesseldorf, Germany. This reflects the deep and fruitful collaboration between us. We have already published our results together in conference proceedings and journal article (see the Publication record in the personal portfolio). The collaboration for this work was interrupted between 2020 and 2022 due to the Covid. Considering that some of the restrictions (e.g. international travel, working in lab) begin to ease, the collaboration with University of Duesserdolf has slowly been re-commenced. Recently, we have been working together on the application of porous treatment to turbomachinery blades. The results will be published in the upcoming ASME Turbo Expo 2023, and the title of the paper is "Aeroacoustic Assessment of Porous Blade Treatment Applied to Centrifugal Fans". Professor Frank Kameier has been named as the research visitor to my upcoming EPSRC proposal on leading edge blowing for quiet aerofoil, where the submission date is expected to be before the end of March 2023.
Start Year 2016
 
Title A METHOD FOR FORMING AN ADD-ON COMPONENT FOR AN AEROFOIL 
Description A method is provided for forming an add-on component for an aerofoil which enable the structure of the aerofoil to be tuned in order to reduce the amplitude of sound produced at frequency f peak when air flows in a flow direction from the leading edge over the trailing edge of an aerofoil. The method applies both to add-on components having a slitted formation and a Double-Rooted Trailing Edge Serration (abbreviated to "DRooTES"). 
IP Reference WO2020229829 
Protection Patent application published
Year Protection Granted 2020
Licensed No
Impact This invention describes a novel, yet simple trailing edge treatment to enable aerofoil self-noise reduction with frequency-tuning capability based on the acoustical interference mechanism. Using a structurally-rigid slit and DRooTES trailing edges, it can facilitate a phase-cancellation of the acoustical pressure waves between two scattering sources located at the slit root and tip (or the double roots for the DRooTES). By forcing the condition of the acoustical destructive interference to esta
 
Title Noise Reduction to the Trailing Edge of Fluid Dynamic Bodies 
Description A fluid dynamic body having a trailing edge with a pattern formed thereon, the pattern can include a plurality of smoothly surfaced adjacent members with respective interstices therebetween, wherein at least one of the interstices completely contains a porous barrier. In some embodiments, the porous barrier can obstruct fluid flow through the respective interstice between a first surface of the fluid dynamic body on a first side of the trailing edge and a second surface of the fluid dynamic body on a second side of the trailing edge. This helps to reduce noise produced at the trailing edge. In some embodiments, the fluid dynamic body is a wind turbine blade or an air-engine blade. 
IP Reference US2017298740 
Protection Patent granted
Year Protection Granted 2017
Licensed No
Impact The poro-serrated technology has been further developed in the EPSRC project (EP/N018737/1) to improve the manufacturing method when implementing non-homogenous materials to an industrial aerofoil blade.
 
Description Co-chair in the Structured Session: "Aeroacoustics: Airfoil Modifications for Low Noise" at Inter-Noise 2016 (Hamburg, Germany) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Co-organising in the
I am the co-session chair in the Structured Session: "Aeroacoustics: Airfoil Modifications for Low Noise" at Inter-Noise 2016, Hamburg, Germany. This conference was attended by more than 500 people, including delegates from the industries. It was a successful event that attracted sizeable audiences (academics and industrial delegates) to this session. I also have an opportunity to disseminate some of my research group's latest results. It sparked many questions during the session, and further discussion afterwards.
Year(s) Of Engagement Activity 2016
URL http://www.internoise2016.org/program/technical-sessions/#c382
 
Description Demonstration at University open day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Every year Brunel University will organise many open days in which I regularly involve in the presentations on research and teaching activities to the visitors. The open days in Brunel provide a good opportunity to inform the general public about the innovative research conducted in the area of aircraft noise reduction. I have the opportunity to demonstrate the plasma actuators that could be used for aircraft engine fan noise reduction, which generates interests among the visitors and encourages more students to engage in the STEM education.

Given the close proximity of Brunel University to Heathrow Airport and the noise-sensitive areas that are under the flight paths, my research on the plasma actuators (EP/K002309/1), serration technology (EP/N018737/1) and porous treatments (QUADPORS, EP/V006886/1) that aim to reduce fan noise radiated from the aircraft engine has a high potential to achieve significant social impact. This is because a lot of these visitors are from the local area who are genuinely concerned about the impact of the aviation noise and are interested to know more about the recent trend in the technological development. My EPSRC-funded research is well placed to demonstrate that the academic research community as well as the government are motivated to continuously develop the latest technology to address this important societal issue.
Year(s) Of Engagement Activity 2013,2014,2015,2016,2017,2018,2019,2023
 
Description ICURe engagement activities 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact In April 2018 I received an award from the Innovate UK on ICURe, which is a programme of commercialisation support for teams of academic researchers wishing to explore the commercial potential of their research. My PhD student Jonne Jeyalingam was employed as the early career researcher for this programme to embark a three-month programme to engage and speak directly with technical representatives and managers of over 20 technological companies and governmental organisations on the poro-serrated aerofoil developed in the EPSRC "Quiet Aerofoil of the Next-Generation EP/N018737/1" project, as well as the plasma-based flow control for aeroacoustics application developed in the EPSRC "Reduction of aerofoil self-noise by surface plasma technique" project. This public engagement not only helps to develop and enhance his entrepreneurial skills, but also strengthen links between academic and industrial communities. Our engagement of many fan-based companies (wind turbines, aero-engine, drone, and home-appliance) in this programme allows the opportunity for further collaboration to raise the technological readiness level of the low-noise aerofoil together, and to accelerate the implementation of our product in the industrial applications. Post award engagements with some of these companies are ongoing.
Year(s) Of Engagement Activity 2018
 
Description Invite lecture at University of Southampton - Aerofoil noise reduction by active or passive flow control - opportunities and challenges 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact This invited lecture provides an opportunity for me to disseminate some of the most recent research outcomes from my group to other audiences, primary academic colleagues and postgraduate students (PhD and MSc). I also discussed some of the opportunities and challenges facing the aerofoil noise, which sparked many interests and exchanges of new research ideas during the lecture, and afterwards.
Year(s) Of Engagement Activity 2018
URL https://www.southampton.ac.uk/engineering/news/seminars/2018/11/13-tze-pei.page
 
Description Invited lecture at University of Southampton - Experimental study of aerofoil noise sources in the spatial and temporal domains 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact This invited lecture provides an opportunity for me to disseminate a novel experimental technique developed in the project. The main objective of this paper is to exploit the deterministic turbulent boundary layer to either disrupt an existing acoustic scattering mechanism, or reconstruct a new acoustic scattering scenario to enable the ensemble-averaging and wavelet analysis to study the aerofoil trailing edge noise source mechanisms in the spatial, temporal and frequency domains. One of the main attractions of this technique is that the experimental tool does not need to be extremely high fidelity as a priori in order to fully capture the pseudo time-resolved boundary layer instability or turbulent structures. In one of the case studies presented here, roll-up vortices of the order of ~kHz can be captured accurately by a 15 Hz PIV. A single hot-wire probe is also demonstrated to be capable of reconstructing the turbulent/coherent structures in a spatio-temporal domain. This novel technique can be extended to other self-noise scenarios when the aerofoil trailing edge is subjected to different flow control treatments, such as the porous structure, surface texture, or finlet, which are largely not understood very well at present. I am pleased that this lecture sparked many interests and exchanges of new research ideas during the lecture, and afterwards.
Year(s) Of Engagement Activity 2021
URL https://www.southampton.ac.uk/engineering/news/seminars/2021/10/26-experimental-study-of-aerofoil-no...
 
Description Organiser in a special session for the 23rd International Congress on Acoustics ICA2019 (Aachen, Germany) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact I am the organiser for the 23rd International Congress on Acoustics (ICA2019) for the special topic Flow Acoustics: "Aeroacoustics and Flow Controls", Aachen, Germany (9-13 Sep 2019), which was attended by more than 500 people, including delegates from the industries. It was a successful event that attracted sizeable audiences (academics and industrial delegates) to this session. I also have an opportunity to disseminate some of my research group's latest results. It sparked many questions during the session, and further discussion afterwards.
Year(s) Of Engagement Activity 2019
URL http://www.ica2019.org/fileadmin/ica2019.org/program/ICA_2019_Call_for_Papers.pdf
 
Description Organising workshop (Serration Technology on Airfoil: Unsteady Aerodynamic and Aeroacoustics) at Lorentz Center, Netherland 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact I am one of the scientific organisers of this workshop. The aim of this workshop was to bring together senior experts and a new generation of researchers from universities, research establishments, wind turbine and aircraft engine industry: aerodynamicists, acousticians, experimentalists, numerical experts and mathematicians. The idea was to assess the state-of-the-art of the prediction methods and the experimental capabilities, to identify challenges and to investigate possibilities for future co-operations.
Year(s) Of Engagement Activity 2016
URL https://www.lorentzcenter.nl/lc/web/2016/848/info.php3?wsid=848&venue=Snellius
 
Description Outreach activities at the new "STEM Centre" at Brunel University 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact The new £5 millions "STEM Centre" at Brunel offers an opportunity in which my research students and myself will set up programme to get the general public and school students involved in scientific activities and inform them the innovative research conducted in the areas of aircraft and wind turbine noise reduction. We also set up simple experiments (e.g. plasma actuators for active control, and serration and porous treatment for the bio-inspired flow control) to encourage the school students to take part in the exercises. We always receive positive feedback from the school students as they find it fascinating that the unique bio-features from owl can be mimicked to the fan blade to achieve good aeroacoustic and aerodynamic performances. We also receive feedback from schools about the increased interest in the aeroacoustic field.
Year(s) Of Engagement Activity 2016,2017,2018,2019,2023
 
Description Participating in the "Made in Brunel" public showcase 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact My research team and I participated in the "Made in Brunel" public showcase held at OXO Bargehouse to demonstrate our next-generation low noise fan blade. The aim is to raise public awareness of the efforts from scientific-community to reduce wind-turbine noise, and how bio-inspired concepts (e.g. serration from owls) can realise this goal. Results from my two EPSRC projects (Reduction of aerofoil self-noise by surface plasma technique EP/K002309/1, and Quiet Aerofoil of the Next Generation EP/N018737/1) were showcased in this event. We generated a lot of interests and some attendees are quite fascinated by the capability of serrated fan blade in the reduction of noise. This event was not organised in 2020 due to the pandemic lockdown.
Year(s) Of Engagement Activity 2018,2019
URL http://madeinbrunel.com/
 
Description Publication of research activities in magazine - taking inspiration from nature for a new generation of quiet aerofoils 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Research Features magazine is a free online portal aims to disseminate the latest research outcomes to mass audiences, including policymakers and industrial/business. Since the publication of our research in the low-noise aerofoil in the Research Feature magazine, we have been receiving enquiries from general public to seek further information.
Year(s) Of Engagement Activity 2017
URL http://researchfeatures.com/2017/11/02/new-generation-quiet-aerofoils/
 
Description Update on Aerospace Research activities at Brunel 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact As the lead for the Aerospace Research Group, I actively establish and develop sustained academic and professional networks nationally and internationally which bring benefit to the University. I invited the Director of the German Aerospace Centre (DLR) for the Institute of Electrified Aero Engines, Professor Lars Enghart, to participate in person for the "Brunel Aerospace Research" seminar on 20 June 2022. Other external participants include academics from TU Cottbus (Germany), and Southern University of Science and Technology (China). Internal invitations were sent to colleagues both within and outside the Aerospace Research Group, as well as academics from other departments. During the meeting, I disseminate major results of my three EPSRC projects (EP/K002309/1, EP/N018737/1 and EP/V006886/1). At the conclusion of this seminar, several avenues for research collaborations have been discussed and currently in development.
Year(s) Of Engagement Activity 2022