Pairing and Acoustics of Azimuthally Perturbed Vortex Rings

Abstract

The study of the interaction of the perturbed thin vortex rings with phase differences of Delta gamma = 0 and pi for the wavenumber m = 4 are investigated numerically. The flow is assumed inviscid and incompressible. The model of the thin vortex rings is based on the vortex blob method, which gives the global dynamics of the vortices. By using acoustic analogy, the far field sound pressure of the evolution of the vortex system is found. Results show that, the phase difference of the two perturbed vortices causes different development of the vortex patterns of the vortex rings, resulting in instability and higher the sound pressures of the vortex system.