Improved SA Turbulence Model For Hovering Rotor Using Production Limiter

Abstract

The simulation of hovering rotorcraft flow continues to present formidable challenges in computational fluid dynamics, owing to its intrinsically unsteady characteristics and the complexity of rotor wake vortex interactions. Conventional turbulence models such as the Spalart-Allmaras (SA) model face difficulties in accurately capturing rotor wake structures, often resulting in excessive vortex dissipation. This study proposes a production limiter for the SA model to address the over-production of turbulent eddy viscosity in wake regions. The limiter incorporates a shielding function from the delayed detached eddy simulation formulation to preserve the original SA model behavior within boundary layers while targeting outer wake regions. Validation through turbulent flat plate and transonic airfoil test cases demonstrates that the production limiter maintains boundary layer prediction accuracy while effectively controlling turbulent eddy viscosity in wake regions. Application to the HVAB rotor shows significant improvements in vortex preservation and aerodynamic performance prediction with minimal computational overhead.