Free-Wake Euler and Navier-Stokes CFD Method and its Application to Helicopter Rotors Including Dynamic Stall.

摘要

This report summarizes the results of the research in two parts. Part I describes the development and application of a free-wake Euler and Navier-Stokes computational fluid dynamics method, called TURNS, for helicopter applications. This finite-difference, implicit, upwind numerical method uses structured grids, and has been used for calculating the viscous, three-dimensional flowfields of rotors in hover, forward flight, blade-vortex interactions, and high speed impulsive noise. The good agreement of numerical results with experiments for surface pressures, wake trajectory, thrust, power, Figure of Merit, and acoustic wave forms indicate the accuracy and suitability of the numerical method. It is demonstrated that both aerodynamics and acoustics information can be obtained in a single solution of the governing equations. In Part II, the unsteady flowfield results of a two-dimensional oscillating wing are presented for five widely used turbulence models and compared with experiments. The accuracy and suitability of turbulence models for unsteady separated flow axe discussed.