Aeroacoustic Study of the Interaction of a Rotating Blade with a Batchelor Vortex

The aeroacoustic response of the orthogonal interaction of a rotating blade with an isolated Batchelor vortex is studied by means of numerical simulation. The relative influence of the vortex tangential and axial velocity on the blade aerodynamics and on the acoustics radiated in the far field is analyzed by comparing the interaction with a Batchelor vortex to the interactions considering the vortex tangential or axial velocity components. Analyses show that the vortex tangential velocity contributes mostly to the noise level at low frequencies, whereas the vortex axial velocity is responsible for the contribution at high frequencies. For the range of frequencies in between, the interaction noise results from constructive interferences of the noise radiated separately by each velocity component of the vortex.