EXPERIMENTAL AND NUMERICAL INVESTIGATION OF SHOCK-WAVE PROPAGATION INTHE 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 whi ch use the KZK equation with the equivalent boundary condition is foun d. Both measurements and simulations indicate that there is a connecti on between the shock and the signal generated at the center of the sou rce, and that it is superposed on a ''background signal'' which is con nected to the signal generated near the edge of the source. The measur ements and simulations also indicate that the shock speed may depend u pon the source amplitude. Finally, the simulations show that the magni tude of the shock at some distance from the focal point (measured alon g the symmetry axis) reaches a level of saturation.