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使用直接数值模拟技术研究两个声耦合气泡的过渡频率

Investigation of transition frequencies of two acoustically coupled bubbles using a direct numerical simulation technique

Masato Ida

AI总结:

通过直接数值模拟技术验证了理论预测的两个声相互作用气泡的三个过渡频率的存在,其中两个对应于自然频率,另一个不对应于自然频率。

摘要:

关于两个声相互作用气泡的“过渡频率”的理论结果已通过数值验证。Ida [Phys. Lett. A 297 (2002) 210] 提供的理论预测每个气泡存在三个过渡频率,每个过渡频率下气泡脉动与外部声场之间的相位差为 π/2,而先前的理论仅预测了引起这种相移的两个自然频率。即,三个过渡频率中的两个对应于自然频率,而剩余的一个不对应。在后续论文 [M. Ida, Phys. Rev. E 67 (2003) 056617] 中,理论上表明,除自然频率外的过渡频率可能导致作用于脉动气泡之间的次级 Bjerknes 力的符号反转。在本研究中,我们采用直接数值模拟技术,使用包含表面张力项的可压缩 Navier-Stokes 方程作为控制方程,通过观察气泡的脉动幅度和平动运动方向(两者均随驱动频率变化)来研究两个耦合气泡的过渡频率。数值结果再现了最近的理论预测,验证了不对应于自然频率的过渡频率的存在。

英文摘要:

The theoretical results regarding the ``transition frequencies'' of two acoustically interacting bubbles have been verified numerically. The theory provided by Ida [Phys. Lett. A 297 (2002) 210] predicted the existence of three transition frequencies per bubble, each of which has the phase difference of $π/2$ between a bubble's pulsation and the external sound field, while previous theories predicted only two natural frequencies which cause such phase shifts. Namely, two of the three transition frequencies correspond to the natural frequencies, while the remaining does not. In a subsequent paper [M. Ida, Phys. Rev. E 67 (2003) 056617], it was shown theoretically that transition frequencies other than the natural frequencies may cause the sign reversal of the secondary Bjerknes force acting between pulsating bubbles. In the present study, we employ a direct numerical simulation technique that uses the compressible Navier-Stokes equations with a surface-tension term as the governing equations to investigate the transition frequencies of two coupled bubbles by observing their pulsation amplitudes and directions of translational motion, both of which change as the driving frequency changes. The numerical results reproduce the recent theoretical predictions, validating the existence of the transition frequencies not corresponding to the natural frequency.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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