超声造影剂微泡非线性声学特性的数值仿真

Numerical simulation on the nonlinear acoustic characteristics of ultrasonic contrast-agent

以空气泡为例,采用描述气泡半径运动的Rayleigh-Plesset方程,对其在高频声压辐照下的非线性振荡,散射声场和散射截面进行理论和数值研究,为获取更清晰的图像提供理论依据。结果表明:激励声压的频率在微泡的固有谐振频率附近时,可以产生强的二次谐波散射声压。同时,提高入射声强可以增大二次谐波散射截面,但不能改变基波散射截面。

Aimed to provide theoretical basis for acquiring more distinct images, some theoretical and numerical research on nonlinear vibration, scattering acoustic field and scattering cross section of bubbles under high frequency acoustic radiation have been done based on the Rayleigh-Plesset equation describing bubbles＇ radius movement. The simulations show that strong secondary harmonic scattering acoustic pressure can be obtained when the frequency of driven acoustic pressure is near bubbles＇ inherent frequency, while higher incident acoustic pressure can increase secondary harmonic scattering cross section rather than fundamental wave scattering cross section.