Review of Tidal Turbine Wake Modelling Methods – State of the Art th Europea 13 th 13 ean Wave and Tid idal l Ener ergy Con Conference – EWTEC 2019 Ellen Jump 1 , Alasdair Macleod 1 , Tom Wills 2 1. Offshore Renewable Energy Catapult 2. Nova Innovation This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 745862.
CONTENT • EnFait project introduction • Aims of the review • Wake phenomena • Wake influences • Physical modelling • Numerical modelling • Array interaction modelling • AIM in the EnFait project Commercial in Confidence
The EnFAIT Project • €20m, 5 -year Horizon 2020 project • World’s first offshore tidal array (Shetland) • Deploy 3 additional Nova M100 turbines • Reduce the cost of tidal energy A huge step towards a commercial, bankable tidal energy sector Commercial in Confidence
Review Scope & Aims • Tidal stream, horizontal axis tidal turbines (HATT) Initial T4-6 location • Wake phenomena, wake interaction Final T4-6 location • Existing T1-3 location Array interaction modelling (AIM) method • Inform tida In tidal l arr array la layout Commercial in Confidence
Wake Phenomena accelerated flow meandering around wake tip vortices shear layer velocity recovery velocity deficit within wake inner wake swirl asymmetry near wake mid wake far wake (10-20D) Commercial in Confidence
Wake Influencing Factors waves tidal speed shear profile and direction water depth, hub height tower shadow, device turbulence generated turbulence bathymetry Commercial in Confidence
Turbine Representations in Models Velocity Swirl Tip Vortices Deficit x x ✔ Actuator Disk Blade Element x with additions ✔ Method with additions ✔ ✔ Actuator Line ✔ ✔ ✔ Fully-Resolved Commercial in Confidence
Physical Modelling of Wakes • Lab testing ◦ Reduced cost and risk ◦ Wake behaviour, influences ◦ Scaling challenges – near wake ◦ Blockage influences ◦ Measurement methods • At-sea testing ◦ True representation ◦ Multiple interacting influences ◦ Commercial sensitivity Figures – scale turbine testing as part of the MONITOR project Commercial in Confidence
EnFAIT Wake Modelling – Initial Prediction from ADCP Data • Wake characteristics Turbulence ◦ Direction ◦ Behaviour in flow ◦ • Current and wave interactions Commercial in Confidence
Numerical Modelling of Wakes • BEMT • CFD methods – many variations ◦ RANS • Smooths turbulent eddies • Turbulence model dependent on application ◦ LES • If local flow/blade generated detail needed • RANS / Synthetic Eddy (SEM) inlet conditions ◦ Hybrid Methods • Reduce complexity • Small scale turbulence at wall regions • DES Initial EnFait CFD Simulation, • Improved Scale-Adaptive Simulation (ISAS) P. Ouro Commercial in Confidence
Array Interaction Modelling Ouro et al. Analysis of array spacing on tidal stream turbine farm performance using Large-Eddy Simulation. Under review in J Fluids Structures Commercial in Confidence
Array Interaction Modelling in EnFait Commercial in Confidence
Summary • EnFAIT – demonstrate the world’s first tidal array, and reduce tidal LCOE • Wake phenomena and influencing factors • Physical modelling of wakes • Numerical modelling of wakes • Array interaction modelling ◦ Which phenomena need to be represented? • Array modelling approach for EnFAIT ◦ Practical, robust, industry appropriate approach Commercial in Confidence
CONTACT US www.enfait.eu Email: info@enfait.eu Tel: +44 (0)131 241 2000 This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 745862.
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