Aeroacoustic noise generation in compressible vortex reconnection

We explore the noise generation mechanisms in the compressible vortex reconnection of two anti-parallel vortices of equal strength via a high-order DNS of the fully compressible Navier-Stokes equations. Over a range of vortex Reynolds number (1500-12,000, where Re = circulation/viscosity), we show that noise generation occurs in the reconnection zone, particularly at the bridges, with a directivity in the lateral direction. A moderate correlation between the generated noise and Mach number in the vortices’ advection direction is found. Finally, the simulation of Re = 12,000 captures at a later time a second reconnection of the small-scale thread structures reasserting vortex reconnection cascade as a realistic physical explanation of the turbulence cascade phenomenon.