Large Eddy Simulations (LES) have in recent years been applied to studies of wind turbine wakes and their interactions with the atmospheric boundary layer [1-5]. While many subgrid-scale (SGS) models have, over the years, been proposed (see [6]), the effects of various SGS models in simulations of wind turbine wakes has not been documented in great detail yet. In this study, we explore such effects in simulations of single wind turbine under laminar and turbulent inflow conditions. LES of wind turbine wakes are carried out using the actuator line (ACL) model [7]. To examine the effect of using different turbulent closures, various SGS models including the Smagorinsky model and two variants of the mixed-scale model presented in [8], are tested. Simulations are performed on a single turbine placed in uniform and turbulent inflow. Four simulations are performed to identify the role of SGS modeling on the wake characteristics. It is shown that in the near wake region, the mean velocity profiles in the wake are rather insensitive to the SGS model while the different models predict a different far wake. Considerable effects can be observed in profiles of second-order statistics of resolved velocities, as well as in profiles of subgrid-scale eddy viscosity. From comparisons of laminar and turbulent flow it is confirmed that the wake region in laminar inflow case grows less rapidly and extends further downstream in a more concentrated fashion, as compared to the turbulent inflow case, in which the wake grows (i.e. the velocity recovers) much faster.
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