Comparison of Analytical Wake Models with CFD Study of Savonius Vertical Axis Wind Turbine

Wake characteristics of wind turbines such as wake width, velocity deficit, and turbulence intensity are important factors for optimal placement of wind turbine rotors in an array in a typical wind farm. Reduced-order analytical wake models are useful tools in wind-farm layout design due to their simplicity and low computational demand. However, the suitability of such reduced-order models has to be tested with more refined CFD studies before they can be deployed in the optimization of wind-farm layout. In this study, a detailed comparison of widely used analytical wake models with CFD studies on static and dynamic Savonius Vertical Axis Wind Turbine (S-VAWT) is done. The CFD studies involve solving the Reynolds-averaged Navier–Stokes (RANS) equations using finite volume method-based Ansys Fluent. The comparative investigation showed that the analytical wake models reported in the literature are capable of predicting wake characteristics such as the wake width; however, they fail to predict the wake velocity deficit. Moreover, the asymmetry in the wake velocity profile, which is a characteristic feature of S-VAWTs, is not captured by the models. This highlights the need for developing new analytical wake models that are better suited for S-VAWTs.