Lead Research Organisation: University of Glasgow
Department Name: School of Engineering


Among technically and economically viable renewable energy sources, wind power is that which exploitation has been growing fastest in the recent years. This research focuses on modern Horizontal Axis Wind Turbines (HAWT's), which typically feature two- or three-blade rotors. The span of HAWT blades can vary from a few meters to more than 100 meters, and their design is a complex multidisciplinary task which requires consideration of strong unsteady interactions of aerodynamic and structural forces. Some of the most dangerous sources of aerodynamic unsteadiness are a) yawed wind, due to temporary non-orthogonality of wind and rotor plane, and b) blade dynamic stall. These phenomena result in the blades experiencing time-varying aerodynamic forces, which can excite undesired structural vibrations. This occurrence, in turn, can dramatically reduce the fatigue life of the blades and their supporting structure, yielding premature mechanical failures. Events of this kind can compromise the technical and financial success of the installation, which heavily relies on fulfilling the expectations of minimal servicing on time-scales of the order of 10 to 30 years. These facts highlight the importance of the aeroelastic design process of HAWT blades. The unsteady aerodynamic loads required to determine the structural response must be understood and accurately quantified in the development phase of the turbine. Due to the sizes at stake, in most cases it is infeasible to perform aeroelastic testing, not only from an economic but also logistic viewpoint. Hence these aeroelastic issues can only be tackled by using accurate simulation tools.The general motivation of this project is two-fold: it aims both at enriching the knowledge of unsteady flows relevant to wind turbine aeroelasticity, and advancing the state-of-the-art of the computational technology to accomplish this task. These objectives are pursued by using a novel Computational Fluid Dynamics (CFD) approach to wind turbine unsteady aerodynamics. The unsteady periodic flow relevant to aeroelastic analyses is determined by solving the three-dimensional unsteady viscous flow equations with the nonlinear frequency-domain (NLFD) technology. The NLFD-CFD approach has been successfully applied to fixed-wing and turbomachinery aeroelasticity. This research will exploit this high-fidelity methodology to enhance the understanding of the severe unsteady aerodynamic forcing of HAWT blades, and substantially reduce computational costs with respect to conventional time-domain CFD analyses. This method is particularly well suited to investigate the unsteady aerodynamic blade loads associated with stall-induced vibrations and yawed wind. On the other hand, this technology will greatly help designers to develop new blades without relying on the database of existing airfoil data on which the majority of present analysis and design systems depend. One of the main results of this project will be to greatly reduce the dichotomy between the conflicting requirements of physical accuracy and computational affordability of the three-dimensional unsteady viscous flow models for wind turbine unsteady aerodynamics and aeroelasticity. The achievements of this research will benefit the British and European industry in that they will offer an effective tool to design more efficient and reliable blades. The NLFD-CFD technology will also provide deeper insight into unsteady aerodynamic phenomena which affect the fatigue life of wind turbines. In the next few years, the certification process of wind turbines will enforce stricter requirements on the industry. The developed technology will support the analyses required to meet enhanced certification standards. The Unsteady Aerodynamics Research Community as a whole will also benefit from this research, because its findings will enhance and consolidate the deployment of the NLFD technology in rotorcraft, turbomachinery, and aircraft aeroelasticity.


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Campobasso M (2009) Wake-tracking and turbulence modelling in computational aerodynamics of wind turbine aerofoils in Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy

Description This research has developed a harmonic balance compressible Navier-Stokes (NS) computational fluid dynamics (CFD) solver for wind turbine (WT) unsteady aerodynamics and aeroelasticity. This novel computational aerodynamics technology has reduced by up to 50 times with respect to the conventional time-domain NS solution approach the runtime required for calculating the unsteady loads on WT blades. Further substantial performance enhancements of the new technology have been achieved by developing a new low-speed preconditioning method and a hybrid shared/distributed parallelisation to efficiently run a parallel HB NS simulation with many thousands of cores. The developed software has an extremely high parallel efficiency and is very user-friendly. These features enables the use of COSA for both frontier research and advanced high-fidelity industrial design of wind turbine rotors.
Exploitation Route The COSA CFD code has been already used by Dr. Campobasso's research group within a research contract with a wind turbine manufacturer. The code continues to be developed by Dr. Campobasso's group, and shortly it will be ready for frontier industrial analysis and design tasks. The HB NS technology can be used for wind turbine aerodynamic and aerostructural design, but also for aircraft wing, rotorcraft, and turbomachinery blade aerodynamic analyses. The CFD HB COSA solver (including a user manual and a suite of test cases) has been installed on ARCHER and made available to all ARCHER users. The COSA code is being used for collaborative research projects, in cluding that on three-dimensional vertical axis wind turbine aerodynamics with the University of Florence, and is about to be further developed and used for new industrial projects to commence in 2016.
Sectors Energy,Environment,Manufacturing, including Industrial Biotechology

URL https://www.sites.google.com/site/mscampobasso/
Title COSA Harmonic Balance CFD code 
Description The COSA Harmonic Balance and time-domain code is a Computational Fluid Dynamics code for the rapid analysis of wind and tidal turbine periodic flows. It can efficiently use very large high-performance computing resources to investigate challenging and outstanding problems of renewable energy fluid machinery. The code is installed and used on the UK National supercomputing service ARCHER and developed in collaboration with EPCC. The code has been used for many cutting-edge investigations into the unsteady fluid mechanics of horizontal axis and vertical axis renewable energy machines and more recently also for shedding new light and providing new design guidelines for the development of oscillating wings for the generation of tidal power. 
Type Of Material Improvements to research infrastructure 
Year Produced 2015 
Provided To Others? Yes  
Impact The COSA code has recently been used for investigating the potential of oscillating wings to efficiently harvest tidal power. This research has resulted in new findings, reported in the International Journal of Marine Energy in 2016, key to the development of energy harvesters with higher energy conversion efficiency. The COSA code is now being used to resolve outstanding questions in the unsteady aerodynamics of horizontal axis wind turbines in yawed flows. The use of the harmonic balance technology for these analyses reduce computational costs by more than 50 times over conventional methods, enabling one to tackle with adequate fidelity problems which thus far could not be investigated thoroughly due to massive computing power requirements. Key publications on these aspects will be produced in the next 12 months. 
Description Vertical axis wind turbine computational aerodynamics 
Organisation Technical University Berlin
Department Institute of Fluid Dynamics and Technical Acoustics
Country Germany 
Sector Academic/University 
PI Contribution The Wind Energy group at the Technical University of Berlin provided three-dimensional vertical axis wind turbine data computed with their in-house code based on lifting line theory and a free-vortex method. These data have been used for a unique cross-validation of the high-fidelity supercomputing-based Computational Fluid Dynamics code COSA developed by Dr. Campobasso's group and the engineering code developed at the Technical University of Berlin. These analyses have resulted in substantial consolidation of both computer-based analysis and design technologies, a step of crucial importance to the deployment of both methods for industrial analysis and design tasks.
Collaborator Contribution Dr. Campobasso's group has contributed highly-resolved vertical axis wind turbine aerodynamic data obtained with the group's research code COSA, which in this project was run on the largest clusters of the Hartree Centre at the Daresbury Laboratory.
Impact The first output is a peer-reviewed paper to be presented at the ASME Turbo Expo Technical Conference in North Carolina in June 2017. The paper is entitled: Three-dimensional Aerodynamic Analysis of a Darrieus Wind Turbine Blade Using Computational Fluid Dynamics and Lifting Line Theory, and is coauthored by memebrs of Dr. Campobasso's team, members of the Research Group at the Technical University of Berlin and members of a second research partner, The Department of Industrial Engineering at the University of Florence in Italy. A more detailed journal paper is also in preparation.
Start Year 2016
Description Vertiical axis wind turbines at University of Florence 
Organisation University of Florence
Department Department of Industrial Engineering (DIEF)
Country Italy 
Sector Academic/University 
PI Contribution My team used the computational fluid dynamic technology developed in EPSRC grant EP/F038542/1 to investigate the complex unsteady aerodynamics of an agreed vertical axis wind turbine (VAWT) that our research partners in Florence have analysed using a commercial CFD package. The purpose was to further assess the computational efficiency and the usability of our research code for complex realistic design task. This work has resulted in a joint paper presented at an ASME Conference in Montreal in summer 2015, in 2 new joint articles presently being prepared, and in a joint project in which my team and the group in Florence are using the research code we have developed for an extremely large pioneering computer-based investigation of 3D VAWT aerodynamics carried out at the Daresbury Laboratory.
Collaborator Contribution Our collaborators in Florence have contributed to our joint research significant expertise in VAWT aerodynamics, and a large amount of VAWT aerodynamic data we have used to further validate and improve our research computational fluid dynamic technology.
Impact F. Balduzzi, A. Bianchini, F. Gigante, G. Ferrara, M.S. Campobasso, L. Ferrari, Parametric and Comparative Assessment of Navier-Stokes CFD Technologies for Darrieus wind turbines Performance Analysis, paper GT2015-42663, ASME/IGTI Turbo Expo 2015 Technical Conference, 15th-19th June 2015, Montreal, Canada. DOI: 10.1115/GT2015-42663.
Start Year 2014
Title COSA time-domain and harmonic balance Navier-Stokes code 
Description The COSA Navier-Stokes Computational Fluid Dynamics code is an analysis and design computational tool developed with a particular focus on wind turbine aerodynamics. Some of its unique features include an extremely efficient harmonic balance solver, enabling the analysis of utility-scale horizontal axis wind turbines about 50 times more rapidly than conventional time-domain solvers with negligible accuracy penalties with respect to the latter ones. Parallel COSA simulations have been show to scale linearly on all tier 0/1/2 supercomputers used so far well beyond 20,000 cores. This high parallel performance and its high user-friendliness enable us and our partners to use this code both for frontier research and industrial design applications. The code is under continuousfurther development. 
Type Of Technology Software 
Year Produced 2011 
Open Source License? Yes  
Impact We are about to start collaborative projects with major wind turbine manufacturer based on the use of COSA for product development. 
Description HPC-CORE International Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact The first International Workshop on High-Performance Computing-enabled Computational Fluid Dynamics for Offshore Renewable Energy (HPC-CORE) took place at the University of Lancaster in April 2016 and was meant to bring together young researchers, Academics and Engineers from a wide discipline range, all related to offshore Renewable Energy. Its main purpose is to provide all involved scientific communities with an overview of most recent progress in super-computing-enable CFD to further support and increase the exploitation of offshore Renewable Energy, including wind, tidal current and wave energy. The topics of the Workshop also include environmental science, resource assessment, wind farm and tidal array nanalysis and design, software engineering and key areas of scientific computing, including new HPC approaches (e.g. multi- and many-core architectures). One of the threads of the event is HPC and its use in the considered areas.
The scientific starting point and inspiration of this event has been the knowledge and technologies developed by Dr. Campobasso's EPSRC-funded research in wind turbine aerodynamics and HPC. The event was attended by Postgraduate students and Academics from the UK and abroad. Speakers included Academics from the Technical University of Denmark, and leading UK Research Centres such as EPCC. The final stage of the event consisted of a round-the-table discussion which further promoted multi-disciplinary knowledge transfer. New collaborative cross-disciplinary project proposals have arisen and have been submitted by part of the participants as a result of the formal and informal discussions and sand-pits occurred during the Workshop.
Year(s) Of Engagement Activity 2016
URL https://sites.google.com/site/hpccoreworkshop/