Performance of Turbulence Models in Simulating Wind Loads on Photovoltaics Modules

摘要： The performance of ?ve conventional turbulence models, commonly used in the wind industry, are examined in predicting the complex wake of an in?nite span thin normal ?at plate with large pressure gradients at Reynolds number of 1200. This body represents a large array of Photovoltaics modules, where two edges of the plate dominate the ?ow. This study provided a benchmark for capabilities of conventional turbulence models that are commonly used for wind forecasting in the wind energy industry. The results obtained from Reynolds Averaged Navier-Stokes (RANS) k ? ε, Reynolds Normalization Group (RNG) k ? ε, RANS k ? ω Shear Stress Transport (SST) and Reynolds Stress Model (RSM) were compared with existing Direct Numerical Simulations (DNS). The mean ?ow features and unsteady wake characteristics were used as testing criteria amongst these models. All turbulence models over-predicted the mean recirculation length and under-predicted the mean drag coef?cient. The major differences between numerical results in predicting the mean recirculation length, mean drag and velocity gradients, leading to de?cits in turbulence kinetic energy production and diffusion, hint at major dif?culties in modeling velocity gradients and thus turbulence energy transport terms, by traditional turbulence models. Unsteadiness of ?ow physics and nature of eddy viscosity approximations are potential reasons. This hints at the de?ciencies of these models to predict complex ?ows with large pressure gradients, which are commonly observed in wind and solar farms. The under-prediction of wind loads on PV modules and over-estimation of the recirculation length behind them signi?cantly affects the ef?ciency and operational feasibility of solar energy systems.