SWEPT2
Lead Research Organisation:
University of Surrey
Department Name: Mechanical Engineering Sciences
Abstract
The SWEPT2 project aims to develop a sophisticated tool for modelling of wind turbine wakes and wake interactions. It is
well known that present wake models are inadequate, especially for application to large offshore wind farms, and have led
to wind farm designs with larger than expected wake losses. Improved wake models are essential for improved wind farm
designs with improved energy yield. Validation of wake models is critical but difficult to undertake at full scale. Therefore,
the EnFlo Laboratory at the University of Surrey will use its specialist wind tunnel facility, the EnFlo stratified flow wind
tunnel, to make measurements on model wind turbines wakes, wake-wake and wake-turbine interactions, in a range of
wind flow conditions. The wind tunnel, one of the very few such facilities globally, is able to simulate stable and unstable
atmospheric wind flow. Atmospheric stability has a large affect on turbine wakes, and the controlled environment of the
laboratory allows more detailed studies than can be obtained from field measurements. One will complement and provide
checks on the other. Both will provide insight into the relevant physics and test-case data for the development of
computational prediction tools in the consortium.
well known that present wake models are inadequate, especially for application to large offshore wind farms, and have led
to wind farm designs with larger than expected wake losses. Improved wake models are essential for improved wind farm
designs with improved energy yield. Validation of wake models is critical but difficult to undertake at full scale. Therefore,
the EnFlo Laboratory at the University of Surrey will use its specialist wind tunnel facility, the EnFlo stratified flow wind
tunnel, to make measurements on model wind turbines wakes, wake-wake and wake-turbine interactions, in a range of
wind flow conditions. The wind tunnel, one of the very few such facilities globally, is able to simulate stable and unstable
atmospheric wind flow. Atmospheric stability has a large affect on turbine wakes, and the controlled environment of the
laboratory allows more detailed studies than can be obtained from field measurements. One will complement and provide
checks on the other. Both will provide insight into the relevant physics and test-case data for the development of
computational prediction tools in the consortium.
Planned Impact
The UK offshore wind sector is projected to grow to £8bn annually by 2020 so the economic benefits estimated to result
from the new wake modelling tool, at over 1% of project costs, could be considerable across the UK investment. Research results will be communicated through the ORE Catapult (a project partners ideally suited to this) and publication
in the relevant journals.
from the new wake modelling tool, at over 1% of project costs, could be considerable across the UK investment. Research results will be communicated through the ORE Catapult (a project partners ideally suited to this) and publication
in the relevant journals.
Organisations
Publications
Hancock P
(2016)
Wind-tunnel simulation of stably stratified atmospheric boundary layers
in Journal of Physics: Conference Series
Hancock P
(2020)
Wind-Tunnel Simulation of Stable Atmospheric Boundary Layers with an Overlying Inversion
in Boundary-Layer Meteorology
Hancock P
(2021)
Wind-Tunnel Simulation of Approximately Horizontally Homogeneous Stable Atmospheric Boundary Layers
in Boundary-Layer Meteorology
Hancock P E
(2021)
Wind-Tunnel Simulation of Approximately Horizontally Homogeneous Stable Atmospheric Boundary Layers
in Boundary-Layer Meteorology (Accepted, to appear.)
Hancock PE
(2018)
Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers.
in Boundary-layer meteorology
| Description | We have developed a globally unique capability for laboratory simulations of the wind - the atmospheric boundary layer (ABL) - suitable for wind turbine and farm studies, using the EnFlo stratified-flow wind tunnel at Surrey, a NERC/NCAS national facility. Wind turbines operate only in the ABL, where the flow is non-uniform and mostly turbulent. The ABL states are very varied from strongly stable to strongly unstable (convective), primarily associated with night-time and daytime conditions, respectively, and have controlling influences on turbine loads and lifetime. In stable conditions, the ABL height can be less than the blade-tip top height, but very much greater (by order 10) in unstable conditions. Stability is mostly measured near the surface (the surface condition), but the temperature gradient - the inversion - above ABL is of vital significance for the stable layer. We first needed to establish how to simulate various stable ABL states before addressing questions associated with turbines themselves. Building on the preliminary work [1], we have found out how to simulate a number of moderately stable states [5, 6, 7]. However, this was in fact much more difficult than anticipated (based on [1]), and is connected with the very varied states that the stable ABL naturally exhibits; vary varied states were seen in our experiments. This also opened up the question 'what is a typical stable ABL?'. In particular, any 'error' that arose in the initial conditions was very persistent. In order to progress, a systematic understanding was required and developed. Also, usefully to a first approximation, it was found that the surface and overlying-inversion conditions are independent of each other. This is also a significant result from a meteorological perspective. We concentrated on a single turbine in stable ABLs, in order to understand how the wake develops, and the implications for a downwind turbine. During the progress of the project it transpired that stable states are of much greater concern than convective states, partly because of their very varied nature, and so the focus in the Surrey work was switched to focus on these alone. The work was also done in conjunction with the EPSRC Supergen-Wind MAXFARM project, and the exchange between the two projects has enhanced both. The MAXFARM project was also selected by EPSRC for part of its strategic review of wind energy research - Powering The Future: https://epsrc.ukri.org/newsevents/casestudies/powering-the-future-of-offshore-wind-farms/ Three databases based on previous and new work have been provided to the project, and a forth is to be developed. 1 Stable ABL, and baseline neutral [1, 2] 2 Unstable ABL, and baseline neutral [3, 4] 3 Stable ABL, no overlying inversion, and baseline neutral [5, 6] 4 Stable ABL, with an overlying inversion [7, 8, 9, 10] (A neutral state is 'between' stable and unstable, and is widely assumed as standard in wind energy studies, though only occurs infrequently or as a long-term (year-long) average, very unrepresentative of fluctuating (i.e. short period) conditions.) New results (for 3 and 4) are being or will be written up for journal publication. [1] Hancock, Pascheke Boundary-Layer Met. 151, 3 (2014) [2] Hancock, Pascheke Boundary-Layer Met. 151, 23 (2014) [3] Hancock, Zhang, Hayden Boundary-Layer Met. 149, 355 (2013) [4] Hancock, Zhang Boundary-Layer Met. 156, 395 (2015) [5] Hancock, Hayden, The Science of Making Torque from Wind, doi:10.1088/1742-6596/753/3/032012 [6] Hancock, Hayden Boundary-Layer Met. 168, 29 (2018) [7] Hancock, Hayden. 13th Conf on Wind Engineering, Univ of Leeds, 3-4th Sept 2018 [8] Hancock, Hayden. Offshore Wind 2018, Bremerhaven, Germany, http://www.rave-offshore.de/en/conference.html [9] Hancock, Hayden. Boundary-Layer Met. doi.org/10.1007/s10546-019-00496-7 (2020) [10] Hancock, Hayden. Boundary-Layer Met. Accepted, to appear. (2021) |
| Exploitation Route | The results, which are still being assessed by partners, showed that the wakes of wind turbines are both directly and indirectly affected by atmospheric stability. There will then be implications for the loading on downwind turbines in a wind farm, in terms of design requirements and life maximization, and, in terms of wind farm operations, on short timescales (e.g 10 minute periods) for optimizing power and energy output against machine lifetime and operation and maintenance costs. It is expected the work will feed into industry standards such as DNV GL's Bladed and WindFarmer software tools, and thereby other industry standards, with implications of improved design and operation of wind turbines and wind farms. Some of the wind tunnel time-domain data was used in an Uncertainty Quantification and Management study. https://cfms.org.uk/news-events-opinions/news/2018/january/cfms-attends-third-uncertainty-quantification-management-group-with-industry/. The wind simulations techniques have been used as a basis for studies on the effect of atmospheric stability on the urban environment, and the movement of pollutants or hazardous substances. |
| Sectors | Energy,Environment |
| Description | At this stage the results are still being assessed by other partners, principally by DNV GL (Bristol). It is expected that the results will contribute to expanding the scope of two industry-standard software tools: Bladed and WindFarmer, in the areas of i) wind turbine and wind farm design, and optimizing energy yield against machine life time predictions, ii) optimized wind farm operation based on short period wind resource prediction (in which the wind conditions are much more varied than they are in long-term averages). Turbine inflow and the influence of wakes from upstream wind turbines are controlling determinants, and the issues are expected to be even more critical as turbines become larger [1]. DNV GL is a major international energy consultancy company, with its internationally leading wind energy consultancy based in Bristol (formerly the UK company Garrad Hassan and Partners Ltd). At present it is not feasible to quantify the benefits in the reduced cost of energy, but both capital and revenue costs are expected to be reduced nevertheless. These pioneering wind simulation techniques that been developed for these wind power studies - through expanding the NERC/NCAS National Facility of the EnFlo Laboratory stratified-flow wind tunnel - have allowed enhanced studies in atmospheric dispersion studies, particularly in urban environments [e.g. 2, 3]. The work also led to an industry invitation to participate in a special session on the effects of flow blockage in large offshore wind farms. [4] [1] Industry panel discussion, Offshore Wind 2018, Bremerhaven, Germany. [2] Marucci, Hancock, Carpentieri, and Hayden, 2016, 12th UK Conf on Wind Engineering, Univ of Nottingham. [3] Hancock and Hayden. 2018, 13th UK Conf on Wind Engineering, Univ of Leeds. [4] Hancock, Placidi and Farr. 2019 Blockage effects as inferred from measurements in the EnFlo stratified-flow wind tunnel. WESC 2019, 17th-20th June, Cork http://doi.org/10.5281/zenodo.3360292 |
| First Year Of Impact | 2018 |
| Sector | Energy,Environment |
| Impact Types | Societal,Economic |
| Description | MAXFARM (MAXimizing wind Farm Aerodynamic Resource via advanced Modelling) |
| Amount | £1,476,695 (GBP) |
| Funding ID | EP/N006224/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 11/2015 |
| End | 05/2019 |
| Description | Mini-Symposium meeting at Wind Energy Science Conference, Cork, 2019 |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Industry/Business |
| Results and Impact | Industry invitation to Surrey team from special-interest group Mini Symposium at Wind Energy Science Conference (2019) to address the question of aerodynamic blockage in wind farms, arising from atmospheric stability and other influences. |
| Year(s) Of Engagement Activity | 2018,2019 |
| Description | SWEPT2 InnovateUK project |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Industry/Business |
| Results and Impact | DNVGL (formally Garrad Hassan and Partners Ltd) is the major internationally-recognised wind-energy consultancy company, and was an industry partner to the MAXFARM project (and also to the SUPETGEN-Wind HUB). MAXFARM was funded under the 2015 Grand Challenges call. The involvement with DNVGL through the SWEPT2 project very usefully added to the shaping of the MAXFARM project as it progressed, and led us to focus entirely on simulating stable winds (and reference neutral winds). Stable winds are particularly complex - and were found to be complex to simulate in the laboratory - and modelling of them has become of major interest to the industry. It is appropriate, therefore, to record this here. |
| Year(s) Of Engagement Activity | 2015,2016,2017,2018 |
| URL | https://gtr.ukri.org/projects?ref=102239 |
| Description | Wind Europe Side Event: Supergen Wind Hub. Wed 3rd April |
| 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 | Wind Europe is the major Europe-wide conference for the WInd Energy Sector. A Side Event programme was given by members of the SUPERGEN-Wind project, covering Theme 1 Planning & Consenting, "Wind energy: economic, social and environmental analysis" (Strathclyde) "MAXFARM (MAXimizing wind Farm Aerodynamic Resource via advanced Modelling)" (Surrey) Theme 2 Design, Manufacturing & Installation, "Servo-aeroelastic tailoring of wind turbines using new active-to-passive control systems" (Bristol) "Integrated Structural and Foundation Monitoring for Offshore Wind Turbines" (Oxford) Theme 3 Operation, Maintenance & Decommissioning, "Optical, Contactless Torque Measurement System /Turbine Generator Condition Monitoring/UK Wind Farm Operational Performance Analysis /Directory of UK based test and demonstration facilities for wind technologies" (Durham) "Offshore Renewables ACcess, Loss Estimation & Safety (ORACLES)" Strathclyde together with Overview of projects and linkages arising from Supergen Wind, Presentations on other projects and linkages (UK/China Joint Projects, AURA/Properity Partnerships). The purpose was to 'showcase' the results of the SUPERGEN-Wind project to this point. An outcome for the MAXFARM project was a new engagement with Enercon specifically focused on the atmospheric boundary layer simulation and the effect of atmospheric conditions on wind turbine wakes. A more detailed presentation was given to meteorology group at Enercon (Bremen) and further exchanges are taking place. |
| Year(s) Of Engagement Activity | 2019 |
| URL | https://www.supergen-wind.org.uk/news/2019/supergen-wind-side-event-at-windeurope-3-april-2019-bilba... |