Blade Vortex Interactions: Experimental Measurements of the Near-Flow Field

抄録

The near-field flow structure of an intense streamwise vortex filament encountering normally with a blade tip vortex was investigated experimentally. Three cases were investigated, direct impingement, interactions on the pressure side and interactions over the suctions side. The effects of blade-vortex interaction were found to be strongly dependent on whether the vortex filament passed over the pressure or suction side of the blade. In case of, zero vortex-blade tip separation (direct impingement), the peak tangential velocity and total circulation of the interaction vortex remained basically unchanged, regardless of downstream distance, but had values larger than the generator vortex, while the core circulation and the core radius increased almost linearly with downstream distance, similar to an undisturbed generator vortex. The maximum total turbulent energy decreased as x/c increased. In summary, the present experiment deals with the normal interactions of streamwise vortex with another tip vortex shed by a blade end-tip, and focuses on the resultant vortex structures and peak values due to the interaction itself.