Parallel Calculation And Simulation Of Nonlinear Ultrasound Field In Absorbing Medium

Just as the important role of numerical simulation in electromagnetic fields for microwave, communications and other fields, the simulation and calculation of sound field is very important for acoustics. In many complex situations, there are no theoretical and experimental methods, but one can make use of the computer simulation environment to conduct simulation and calculation so that numerical results can be obtained. Actual human tissue is a very complex environment, not even symmetrical medium, so in this article we use the method of simulation and calculation to study the property of nonlinear ultrasound field in the multi-layered medium.The research works about improvement of efficiency in numerical calculation of nonlinear ultrasound field and the study of the property of nonlinear ultrasound beams in the multi-layered medium have features as follows:1,In order to improve the time and memory efficiency in numerical calculation of nonlinear ultrasound field,We proposed a parallel computation model:by dividing the field into several sub-regions, using several personal computers and computer networks and MPI parallel programming,the entire ultrasound field would be eventually obtained by calculating these sub-regions respectively. The simulation result of a zeroth-order Bessel field in absorbing medium and a focused Gauss ultrasound field shows the validity of the model.2,Based on the KZK equation, a frequency-domain propagation model of Bessel beam was presented for the fundamental and second harmonic in the multi-layered medium. A parallel computation method is proposed to improve the calculation speed. The property of nonlinear ultrasound field in the multi-layered medium is studied.This thesis not only discusses the whole work but also gives the research results. The suggestion for further work is also described.