Mechanisms and acoustics of blade-vortex-interactions

Paper presents results from a numerical study of blade-vortex interaction (BVI) aerodynamics and acoustics. A two-dimensional model problem was used to do the flow simulation using an Euler- and a Navier-Stokes code. For the turbulent calculations an algebraic Baldwin-Lomax and the two-equation k-e turbulence model was used. The acoustic features of BVI in the near- and midfield were analysed with the flow simulation code and the far-field results were obtained using the three-dimensional Kirchhoff's method. Several crucial parameters of BVI, such as vortex strength, vortex miss distance and the free stream Mach number were varied. The main difference between the inviscid and the viscous flow consideration are pointed out. A comparison with experimental data is done for the important case of a head-on collision.