Improved Rotor Hover Predictions Using Advanced Turbulence Modeling

Abstract

The conventional helicopter rotor S-76 hover performance is numerically investigated using an unstructured grid Navier–Stokes computational fluid dynamics solver. Three S-76 rotor tip configurations, including rectangular straight tip, swept tapered tip, and swept tapered tip with anhedral are investigated, and the results are validated with the experimental data. The rotor figure of merit is predicted over a range of blade collective angles from 4 through 10 deg using a mesh deformation method. A local correlation-based transition model and a stall delay model are investigated with both Spalart–Allmaras’s turbulence model and Menter’s shear stress transport turbulence model to capture complex viscous flow phenomena. The numerical investigations indicate that sufficient numerical accuracy and correct turbulence modeling are both essential for capturing the hovering rotor physics and predicting the rotor performance for the entire collective range.