Unsteady Aerodynamic Modeling and Prediction of Loads for Rotary Wings in Forward Flight

Abstract

Abstract In this effort, a new approach in aerodynamic modeling that accounts for unsteady wake effects as well as viscous friction drag, Leading edge suction effect and post stall behavior for rotary wings in forward flight is proposed. The adopted approach commingles the unsteadiness with the problem of helicopter rotor blade in forward flight. The results of the local normal force coefficients were compared with experimental results of the 7A rotor case study in high speed test point 312 at five non-dimensional radial positions. A CFD solver, HOST/elsA, results are compared with the obtained results at five radii locations. The results show a good agreement between the experimental results and the proposed model preserving the same pattern of variation along the azimuth angle with a slight discrepancy for amplitude and phase angle. Of particular interest, the presented model showed better agreement with the experimental for higher radii locations.