Euler and Navier-Stokes Simulations of Helicopter Rotor Blade in Forward Flight Using an Overlapped Grid Solver

Abstract

Three-dimensional Euler and Navier-Stokes equations are solved using an overlapped grid system to compute the unsteady flow field around helicopter rotor blade in forward flight. To verify the automated overlapped grid solver, the unsteady flow field and airloads on Caradonna-Tung NACA0012 and AH-1G rotor blade models in forward flight were computed. Two equation turbulence model k-ω Wilcox Durbin(WD+) is used. For spatial discretization Roe FDS(Flux Difference Splitting) scheme and Weighted ENO(Essentially Non-Oscillatory) scheme are applied. Good agreement between computed and measured surface pressure distributions was seen for the Caradonna and Tung rotor’s forward flight simulation. The effects of background wake grid spacing, spatial accuracy and viscosity were examined in the AH-1G rotor simulation. Surface pressure distributions, sectional thrust and oscillatory pitching moment coefficients were compared with flight test data. A better variation for sectional thrust and oscillatory pitching moment were found by using the Navier-Stokes analysis.