Aerodynamics and Acoustics of Rotor Blade-Vortex Interactions: Analysis Capability and its Validation

Abstract

As part of an international cooperative program, several aerodynamics and acoustic prediction codes have been recently developed to understand the rotor blade-vortex interaction (BVI) noise. Furthermore, a joint validation activity of these prediction codes was performed with the blade surface pressure and acoustic data taken in the DNW with the 1/7-scale model AH-1 OLS blades. Careful attention has been given to the detailed flow field, especially wake structures during blade-vortex interactionsincluding miss distance between vortex and blade, vortex core size, and tip vortex trajectories. The results of flow field including wake systems from various prediciton codes show some qualitative differences, but the acoustic results using these calculated airload as inputs compare reasonably well with test data.