Effect of vortex profile on sound generation in a non-uniform flow

Propagation of acoustic waves caused by deformation of self-similar vortices in the non-uniform flow is studied by numerical modeling using high-order compact approximation. Since the profile of shedding vortices may vary dramatically, zero-circulation Taylor vortex model and non-zero circulation Vatistas vortex model were considered to compare generated acoustic waves. Stagnation flow at flat plate (case A) and flow around non-rotating rigid cylinder (case B) are taken as prototypes of real-world flows with strong gradients of mean pressure and velocity. Near-wall deformation of initial vortex by the stagnation flow leads to sound radiation from the generated pressure quadrupole. Gradually decaying velocity profile of the Vatistas vortex creates substantially wider pressure quadrupole than that for the Taylor vortex. As a result, both the amplitude and sector of influence for acoustic waves coming out of the Vatistas vortex are larger than those for the Taylor vortex.