Abstract:

A finite difference in time-domain (FDTD) discretization is applied to simulate finite-amplitude sound pulse propagation in biomedical applications. A numerical model requires a method of accounting for correct representation, especially of shorter wave components. These are generated by nonlinear steepening during the propagation. Therefore, the FDTD discretization has to be of low-dispersive and low-dissipative nature. A high-order scheme suitable for the computation of pulsed sound including weak shocks is applied to model a Storz SL 10 shock-wave lithotripter. The SL 10's electromagnetic source generates cylindrically diverging pulsed pressure waves. By reflection at a hemi-paraboidal brass reflector these waves are focused and steepening of the wave profiles causes weak shock-wave generation in the focal region. A high-order method to model curved boundaries (given by the reflector) is presented. Wave profiles predicted are compared with measured ones. Excellent agreements demonstrate the proposed method to be a flexible tool to simulate biomedically applied transient high-energy sound.