A coupled mesoscale–microscale framework for wind resource estimation and farm aerodynamics

• First application of overset algorithm for mesoscale-microscale coupling.
• Coupling demonstrated for coupling multiple cfd codes to WRF.
• Coupling is modular and adaptable to any code.
• Full wind farm simulations shown for two of the codes.

This study discusses the development of a coupled mesoscale–microscale framework for wind resource estimation and farm aerodynamics. WINDWYO is a computational framework for performing coupled mesoscale–microscale simulations. The framework is modular, automated and supports coupling of different mesoscale and microscale solvers using overset or matched grids. The modular nature of the framework and the support for overset grids allows the independent development of mesoscale and microscale solvers and the efficient coupling between the codes. The performance of the framework is evaluated by coupling Weather Research and Forecasting (WRF) model with three microscale computational fluid dynamics (CFD) codes of varying complexity. The solvers used are: (i) UWake: a blade element model with free-vortex wake, (ii) Flowyo: large eddy simulation code with actuator line/disk parametrization of the wind turbine and (iii) HELIOS: detached eddy simulation code with full rotor modeling and adaptive mesh refinement. Power predictions and wake visualization of single turbine and off-shore Lillgrund wind farm in uniform and turbulent inflow are used to demonstrate the capabilities of the framework.