Viscous unsteady flow around a helicopter rotor blade in forward flight

摘要

The unsteady three dimensional Reynolds averaged Navier-Stokes equations are solved for the moving domain in an inertial frame of reference to obtain time-accurate solution for the flow past a helicopter rotor blade in forward flight.The method uses an implicit dual time stepping procedure,a finite volume nodal point spatial discretisation and baklwin-Lomax turbulence model.Results are presented for nonlifting and lifting cases.For the first case,the surface pressure distributions are found to be in good agreement with the experimental results at 89% of the rotor radius,except near the shock which is predicted to lie closer to the leading edge.In the lifting case,the surface pressure distributions compare well with the inviscid solution,both methods predicting the presence of a shock in the outboard region at the azimuth angle of 90 degree.However,the effect of viscosity here turns out to be to weaken the shock as well as to shift the shock position upstream.