Computational Study Using DDES with Higher Order Scheme Modeling to Predict Darrieus VAWT Noise Mechanisms

Abstract

The results of two different numerical techniques, Unsteady Reynolds Averaged Navier Stokes and Delayed Detached Eddy Simulation, are compared to determine their accuracy in the prediction of aerodynamic and aeroacoustic performance of Darrieus vertical axis wind turbines. The flux for URANS simulations is computed using the central differencing scheme according to Jameson-Schmidt-Turkel, while for the DDES computations a higher order discretization namely, weighted essentially non-oscillatory scheme is used. Both aerodynamic and aeroacoustic modeling are evaluated. Then the DDES approach with the higher order scheme is used to investigate the noise mechanisms of Darrieus VAWT at different operating conditions. It is shown that the dominant noise mechanism, when the turbine operates at low and high speed ratios, is a dipole noise, without any contribution from the monopole sound in the time averaged sound pressure signal.