Study of the acoustic nonlinear field generated from a phased array using Gaussian superposition technique

A numerical approach is developed to calculate the nonlinear sound field generated from a phased array based on the superposition technique of Gaussian beams. The parameters of the phased array elements are first estimated from the focal parameters using the inverse matrix algorithm; Then the elements are expressed as a set of Gaussian functions; Finally, the nonlinear sound field can be calculated using the superposition technique of Gaussian beams. A 64×1 phased array is performed in the numerical simulation. In the linear case, the difference between the results of the Gaussian superposition technique and the Fresnel integral is less than 0.5%, which verifies the feasibility of the approach. In the nonlinear case, the nonlinear fields of single-focus and double-focus modes are calculated. The results reveal that the nonlinear effects can improve the focusing performance, and the nonlinear effects are related with the source pressures and the excitation frequencies.