Towards LES-RANS/LES coupling for simulation of a wind turbine rotor in a nocturnal atmospheric condition

Abstract

A segregated approach with either synthetically generated velocity fluctuations or a precursor Large-Eddy Simulation (LES) of the atmospheric boundary layer (ABL) and a subsequent hybrid RANS/LES (HRLS) of the resolved rotor is presented in this paper. At first the approach is validated with synthetically generated velocity fluctuations that resemble neutrally stratified conditions. Subsequently the same turbine is artificially exposed to a stably stratified atmospheric inflow (nocturnal boundary layer) with a comparable mean velocity but different shear and veer characteristics. The HRLS simulations with the neutrally stratified and stably stratified inflow are compared to LESs with an implemented actuator disc (AD) model. The presented work is a first important step towards a digital twin for research wind parks.