Modelling of Wind Turbines as Porous Disks for Wind Farm Flow Studies

Abstract

This study explores the use of porous disks as a modeling approach for wind turbines in both wind tunnel experiments and computational fluid dynamics (CFD) simulations. Experimental testing is conducted on a 0.2m diameter disk made of wired mesh, measuring its wake for several yaw angles. The experiment is recreated in a CFD environment based on the porous-medium approach. The CFD model is validated against part of the measurements and it is used to further investigate the disk wake. Results indicate the porous disk wake resembles that of a wind turbine, especially at a downstream distance of four diameters, and the CFD model effectively captures the disk behavior. Discrepancies between experiment and CFD appear further downstream mainly due to the wake recovery process being only partially captured by the CFD model. When the disk has a yaw angle the wake is displaced laterally, but less than in a widely-accepted deflection model, and this could be due to the lack of wake curling.