Effects of atmospheric thermal stratification on wake aerodynamics of a regenerative wind farm unit

Abstract. The effects of atmospheric thermal stratification on the wake aerodynamics of an isolated unit of a regenerative wind farm unit (RGWF), referred to as a multi-rotor system with lifting device (MRSL), are investigated using precursor-based large-eddy simulations. MRSL is a wind-energy harvesting system designed to realize the concept of RGWF. The core principle of RGWF is to generate large-scale streamwise vortices that enhance the vertical entrainment of kinetic energy, thereby promoting wake recovery and mitigating wake-induced power losses in wind farms. The effectiveness of the RGWF concept has previously been demonstrated under simplified inflow conditions. The present work extends the assessment to realistic atmospheric boundary layers with different thermal stratifications. The results show that, although atmospheric thermal stratification modifies wake dynamics, the beneficial effects of the RGWF concept remain significant under convective (CBL), neutral (NBL), and stable (SBL) atmospheric boundary-layer conditions. In particular, MRSL's wakes recover substantially faster than those of conventional counterparts (i.e., those without lifting devices) across all investigated conditions, further supporting the potential of this technology.