Numerical Analysis of Turbulent Flow Past a Truss Tower for Offshore Downwind Turbines

摘要

For a downwind wind turbine simulation a realistic tower shadowrnmodel is needed. The flow past two dimensional cross sections of bothrna monopile and a truss tower was simulated, and the tower shadowrnmodels of Powles, Blevins and Schlichting were compared withrnnumerical results, assuming linear superposition of wake effects. It wasrnfound that all models have difficulties predicting the mean velocityrnprofile. Spectral analysis showed about an order of magnitude lessrnfluctuations for the truss towers, which might mean less fatigue. Underrnunsteady inflow from a von Karman spectrum, the flow is stillrndominated by fluctuations from vortex shedding.