Abstract:

A Navier-Stokes method based on moving overset grids has been developed to simulate the viscous flow past a helicopter rotor in forward flight. The moving overset grid method is employed to account for the relative motion among the blades which are rotating, cyclically pitching and cyclically flapping. To build the connection among the overset grids quickly, a highly automatic and very efficient method based on Hole Map and Inverse Map is implemented. The cell-centered finite volume method is used as the spatial discretization method. In order to gain both time accuracy and computational efficiency, a fully implicit method (dual-time stepping method) has been developed, in which Newton-like sub-iterations based on LU-SSOR scheme are included. Comparison of the numerical results for a lifting hovering case shows good agreement with the experimental data. Although lacking experimental verification, the numerical result of the lifting forward flight case is reliable.

Key words: helico pter r ot or, forwar d flig ht, Nav ier-Sto kes equations, mov ing ov erset gr ids, finite vo lumemethod, dual-time stepping m et hod