在高密度极限中由共振散射器诱导的非传统的声波传播过渡
Bernard R Matis1, Steven W Liskey2, Nicholas T Gangemi2
1Naval Research Laboratory, Code 7130, Washington, DC, 20375, USA. bernard.r.matis.civ@us.navy.mil.
Scientific reports
|June 27, 2024
概括
实验揭示了超声波在微泡化凝中传播的令人惊的不连续过渡. 这种在关键频率发生的现象为设计用于超声波应用的软材料提供了新的可能性.
科学领域:
- 声学和材料科学 声学和材料科学
- 软物质物理学 软物质物理学
- 非线性声学 非线性声学
背景情况:
- 超声波在含的软材料中的传播可以表现出复杂的行为.
- 之前对非共振内含物或液体泡的研究没有显示不连续的过渡.
- 一个简单的混合模型无法预测微泡化凝中观察到的有效声速.
研究的目的:
- 为了研究超声波传播中的不连续过渡,通过微泡化凝进行传播.
- 为了确定微气泡体积分和临界激发频率之间的关系.
- 探索这种过渡的基础物理及其潜在应用.
主要方法:
- 测量超声波传播的实验通过凝杂的共振封装微泡.
- 封装的微气泡体积分数的系统变化.
- 分析有效相速和临界频率作为微泡度的函数.
主要成果:
- 在临界激发频率下观察到波传播模式的不连续过渡.
- 过渡发生在强散射极限 (平均自由路径<波长) 中.
- 有效相位速度随着微泡体积分数的增加不连续地转移到恒定值,表现出功率定律的依赖性.
结论:
- 观察到的不连续过渡不能用标准理论解释,比如多重散射或粘性效应.
- 假设过渡取决于微泡的共振特性,可能与透理论有关.
- 研究结果表明,这是一种用于设计超声波执行器和开关的柔软材料的新方法,具有可调节的物理特性.
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