Computational analysis of wind-driven Savonius turbine clusters using overset mesh for oblique inflow-induced wake interaction

Abstract

This study examines the aerodynamic coupling and mutual interference of multiple Savonius wind turbines arranged in a horizontal array under oblique inflow conditions, addressing a notable gap in the literature on wind-driven free-rotational dynamics in clustered vertical-axis turbine systems. The flow field around two closely spaced Savonius rotors is investigated using high-fidelity computational fluid dynamics (CFD) simulations across a range of oblique inflow angles to quantify the impact of upstream wake-induced shear layers on downstream turbine performance. A two-dimensional, wind-driven cluster turbine framework is developed using the shear stress transport (SST) k – ω turbulence model in conjunction with an overset (chimera) mesh methodology, enabling accurate resolution of complex inter-rotor wake interactions, unsteady vortex shedding, and transient flow structures. Experimental benchmark data for a single Savonius turbine are employed to validate the numerical framework, establishing a reliable baseline for evaluating inter-turbine aerodynamic coupling. A parametric investigation of inter-turbine spacing ( S ) and oblique inflow angle ( θ ) demonstrates that an inflow angle of α = 50 ∘ produces the most favorable aerodynamic interaction, yielding a maximum power enhancement of 33.81 % at a spacing ratio of S = 0.3 D . The results provide valuable insights into the optimal spatial arrangement and angular alignment of clustered Savonius turbines, highlighting the critical role of upstream wake-induced shear flow in augmenting downstream rotor efficiency and overall energy capture.