Analytical Descriptions of Swirling Wake Profiles

Wake behavior significantly affects the performance and lifetime of wind turbines on which it impacts. This study considers wake profile fits applied to velocity data gathered in a swirling turbulent wake. Wake rotation or swirl has been found to impact wake growth and evolution, and thus both wake deficit and swirl profiles are fit. Specifically, Gaussian and double Gaussian functions are applied to the wake deficit profiles, and Lamb-Oseen and Taylor distributions are used for the tangential velocity profiles. Fits that accurately represent the wake profiles promise to improve wake representations that can be used, for example, in stability theory analyses and wake modeling. The double Gaussian and Taylor vortex distributions were found to best represent the distributions, but Taylor vortex distribution failed to capture the true distribution at some radial locations. An example use of these fits to quantify the impact of swirl on wake evolution is provided.