Helicopter Rotor Airloads Prediction, Using CFD and Flight Test Measurement in Hover Flight

An implicit unsteady upwind solver including a mesh motion approach was applied to simulate a helicopter including body, main rotor and tail rotor in hover flight. The discretization was based on a second order finite volume approach with fluxes given by the Roe s scheme. Discretization of Geometric Conservation Laws (GCL) was devised in such a way that the three-dimensional flows on arbitrary moving grids could be solved. The accurate geometric representation together with the flexibility required for grid displacement was achieved by using a tetrahedral grid. First, the numerical methodology was validated through experimental test data; then, our supposed helicopter configuration was utilized. At the same time, the main rotor loading measurements were done through flight tests. Two methods of moving reference frame (MRF) and viscous/inviscid Dynamic Mesh were compared resulting in robustness of Dynamic Mesh approach. Ultimately, our calculations yielded valid solutions to the blade loading and wake structure.