Experimental and numerical investigation of shock wave propagation in the post focal region of a focused sound field

Experimental and numerical investigations of the shock propagation in the post focal region of a highly intense focusing source are carried out. Close agreement between the measured data and the simulations which use the KZK equation with the equivalent boundary condition is found. Both measurements and simulations indicate that there is a connection between the shock and the signal generated at the center of the source, and that it is superposed on a "background signal" which is connected to the signal generated near the edge of the source. The measurements and simulations also indicate that the shock speed may depend upon the source amplitude. Finally, the simulations show that the magnitude of the shock at some distance from the focal point (measured along the symmetry axis) reaches a level of saturation.