Numerical simulation of parametric sound generation and its application to length-limited sound beam

作者：Nomura Hideyuki^*; Hedberg Claes M; Kamakura Tomoo

来源：Applied Acoustics, 2012, 73(12): 1231-1238.

DOI：10.1016/j.apacoust.2012.02.016

• Nonlinear sound propagation
• Parametric acoustic array
• Length-limited sound beam
• Numerical simulation
• Finite-difference time-domain (FDTD) method

In this study we propose a simulation model for predicting the nonlinear sound propagation of ultrasound beams over a distance of a few hundred wavelengths, and we estimate the beam profile of a parametric array. Using the finite-difference time-domain method based on the Yee algorithm with operator splitting, axisymmetric nonlinear propagation was simulated on the basis of equations for a compressible viscous fluid. The simulation of harmonic generation agreed with the solutions of the Khokhlov-Zabolotskaya-Kuznetsov equation around the sound axis except near the sound source. As an application of the model, we estimated the profiles of length-limited parametric sound beams, which are generated by a pair of parametric sound sources with controlled amplitudes and phases. The simulation indicated a sound beam with a narrow truncated array length and a width of about one-quarter to half that of regular a parametric beam. This result confirms that the control of sound source conditions changes the shape of a parametric beam and can be used to form a torch like low-frequency sound beam.

• 出版日期2012-12