液体表面张力对气泡声散射的影响

The influence of the surface tension of the liquid on bubble’s acoustic scattering

气泡在液体中受液体的表面张力和液体静态压力相当的情况下,研究了表面张力对气泡声散射的影响.建立球形气泡表面的速度和压力连续性方程,并在方程中引入气泡受液体表面张力的影响,求出了气泡在对称振动模式下的散射系数及散射声功率,并进一步推导了在多气泡的情况下的等效入射声场.通过数值分析发现,当球形气泡在液体中受液体的表面张力和液体静态压力相当时,球形气泡的半径约为106m,在此情况下,液体表面张力对气泡声散射的影响只在驱动声场的角频率小于105rad/s时才能表现出来,并且在多气泡的情况下对等效入射声场的等效声压振幅会产生较大影响.而在驱动声场的角频率大于105rad/s的情况下,液体表面张力对气泡的散射系数、散射声功率及等效入射声场声压振幅的影响不明显.对于气泡的声散射问题,气泡受液体表面张力的影响需根据所研究的具体问题进行取舍.

In this situation, the influence of surface tension of liquid on the bubble’s acoustic scattering is studied when the surface tension of liquid is equivalent to the static pressure of liquid. The continuity equation of velocity and pressure in the bubble’s surface is established, and the bubble’s surface tension of liquid is introduced into the continuity equation. We got the scattering coefficient and the scattering sound power of a single bubble in a symmetric vibration mode, and further deduced the equivalent incident sound field in the case of multi-bubble conditions. Numerical analysis shows that spherical bubble radius is about 10^-6m when the surface tension equivalent to the liquid static pressure, in this case, the influence of bubble’s surface tension of liquid on the scattering coefficient and the scattering sound power of the single bubble can be shown when the angular frequency of the driving acoustic pressure is less than 105 rad/s. In the case of multiple bubbles, it will have a greater impact on the sound pressure amplitude of the equivalent incident sound field. While the influence will not appear clearly if the angular frequency of the driving acoustic pressure is bigger than 10^5 rad/s. For the acoustic scattering problem of bubbles, it bases on the specific issue to choose whether the surface tension of liquid should be taken into consideration.