论文标题
在超声激发气泡的振荡中，在1/2级阶次谐波排放的阈值
On the threshold of 1/2 order subharmonic emissions in the oscillations of ultrasonically excited bubbles
论文作者
论文摘要
1/2顺序亚谐音（SH）排放的压力阈值和在超声激发气泡的振荡期间的周期倍增时，当气泡以其谐振频率（FR）的两倍时，被认为是最小的。该估计值基于简化或忽略热阻尼的影响的研究。在这项工作中，研究了超声激发气泡的非线性动力学，以考虑热耗散的核算。使用分叉图可视化结果，这是压力的函数。在这里，我们表明，根据气体，1/2订单SHS的压力阈值在0.5fr <f <0.6fr之间的频率最低。在此频率范围内，1/2顺序SH的产生是由于发生5/2阶超谐音共振引起的。这种振荡的稳定性取决于大小。对于浸入水中的气泡，直径大于1微米的气泡才能在这些频率范围内散发出非破坏性SH。
The pressure threshold for 1/2 order subharmonic (SH) emissions and period doubling during the oscillations of ultrasonically excited bubbles is thought to be minimum when the bubble is sonicated with twice its resonance frequency (fr). This estimate is based on studies that simplified or neglected the effects of thermal damping. In this work, the nonlinear dynamics of ultrasonically excited bubbles is investigated accounting for the thermal dissipation. Results are visualized using bifurcation diagrams as a function of pressure. Here we show that, and depending on the gas, the pressure threshold for 1/2 order SHs can be minimum at a frequency between 0.5fr<f<0.6fr. In this frequency range, the generation of 1/2 order SHs are due to the occurrence of 5/2 order ultra-harmonic resonance. The stability of such oscillations are size dependent. For an air bubble immersed in water, only bubbles bigger than 1 microns in diameter are able to emit non-destructive SHs in these frequency ranges.
