Generation of fractional acoustic vortex with a discrete Archimedean spiral structure plate
Generation of fractional acoustic vortex with a discrete Archimedean spiral structure plate
复制标题
利用离散阿基米德螺旋结构板产生分数声涡旋
DOI：
10.1063/1.5026646
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发表时间：
2018-04-23
影响因子：
4
通讯作者：
Liu, Xiao-Jun
中科院分区：
文献类型：
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作者：
Jia, Yu-Rou;Wei, Qi;Liu, Xiao-Jun
在人工结构板上刻有离散的阿基米德螺旋缝，可以很好地实现分数声涡。对FAV的相场和压力场分布进行了理论研究和数值模拟。结果发现，与拓扑荷（TC）的整数和分数部分相关的相位奇点分别导致压力场轮廓的上半部分中的黑点和压力场轮廓的下半部分中的低强度条纹。文中还详细讨论了TC从1增加到2时FAV的动态变化过程。随着TC从1增加到1.5，相位奇异性的分裂导致FAV的相位偏离整数情况，因此出现新的相位奇异性。当TC m从1.5增加到2时，FAV的两个相位奇异点逐渐接近并最终合并为一个新的中心相位奇异点。我们进一步进行了基于纹影法的实验来演示FAV的生成。
Artificial structure plates engraved with discrete Archimedean spiral slits have been well designed to achieve fractional acoustic vortices (FAVs). The phase and pressure field distributions of FAVs are investigated theoretically and demonstrated numerically. It is found that the phase singularities relating to the integer and fractional parts of the topological charge (TC) result in dark spots in the upper half of the pressure field profile and a low-intensity stripe in the lower half of the pressure field profile, respectively. The dynamic progress of the FAV is also discussed in detail as TC increases from 1 to 2. With increasing TC from 1 to 1.5, the splitting of the phase singularity leads to the deviation of the phase of the FAV from the integer case and hence a new phase singularity occurs. As TC m increases from 1.5 to 2, two phase singularities of the FAV approach together and finally merge as a new central phase singularity. We further perform an experiment based on the Schlieren method to demonstrate the generation of the FAV.