As the United States moves toward utilizing more of its wind and water resources for electrical power generation, computational modeling will play an increasingly important role in improving the performance, decreasing costs, and accelerating deployment of wind and water power technologies. We are developing computational models to better understand the wake effects of wind and marine hydrokinetic turbines, which operate on the same principles. Large wind plants are consistently found to perform below expectations. Inadequate accounting various turbulent-wake effects is believed to be in part responsible for the under-performance.
We show two studies: a wind-turbine array and marine hydrokinetic turbine array. Large-eddy simulations were used as precursors to generate the atmospheric and tidal channel turbulence, respectively. Turbines were then added to the domain, modeled using actuator lines that impose body forces on the flow field equal and opposite to the lift and drag created by the blades. The volume renderings show the low-velocity wakes that originate behind the turbines. The cross-section at the rear of the domain provides some insight into the overall streamwise velocities in the flow domain. And the blue isosurface (high values of the q-criterion, the second invariant of the velocity gradient) in the marine hydrokinetic turbine array illustrates the turbulent structures created in the turbine's wake.