Sound radiation and caustic formation from a point source in a wall shear layer

Compressibility propagates caustic waves from a high frequency point source in a rigid plate-overflowing wall shear layer. Mobile point sources sweep back caustic surfaces and localize the acoustic field energy on caustic surfaces. Mobile caustic surfaces are similar to laminar coherent fluid complexes that contain high vorticity values and explode to eject fluids, causing turbulence in the boundary layer.