Abstract

Combined high-resolution optic and acoustic methods are used for the first time to synchronously detect the fine structure of processes initiated by submersion of a freely falling water drop in a tank with degassed liquid. The emphasis is on analyzing the evolution of the fine structure of flow pattern, the accompanying capillary waves, and the amplitude–frequency characteristics of sound packets. The sequence of acoustic signals includes a shock pulse, which is caused by the initial contact of the drop with the surface of the liquid at rest, and a series of consecutive sound packets. The shock pulse being reliably reproduced in experiments has a complex structure, which includes short segments of high-frequency oscillations and longer segments of low-frequency oscillations. The number of emitted sound packets and their parameters vary in an arbitrary way from one experiment to another while the size of drop and the distance of fall remain invariable. A series of experiments reveals cases of single and secondary packet emission with different spectral compositions of packets, as well as cases of their total absence. Analysis of data is performed with allowance for the effect of the “double layer”, which replaces the coalescence surface of liquids and retains the disturbances caused by transformation of available potential surface energy to other forms, such as thermal energy, pressure disturbance, and energy of fine currents actively affecting the gas cavities.

中文翻译：

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液滴下落对液体的影响引起的声音信号结构的演变

摘要

首次将高分辨率的光学和声学方法相结合，以同步检测过程中的精细结构，该过程是由自由下落的水滴浸没在脱气液体中而引发的。重点是分析流动模式的精细结构，伴随的毛细波以及声音包的振幅-频率特性的演变。声音信号序列包括一个冲击脉冲和一系列连续的声音包，该冲击脉冲是由液滴与静止的液体表面的初始接触引起的。在实验中可靠地再现的冲击脉冲具有复杂的结构，其中包括短段的高频振荡和长段的低频振荡。从一个实验到另一个实验，发出的声音包的数量及其参数以任意方式变化，而跌落的大小和跌落的距离保持不变。一系列实验揭示了具有不同光谱成分的数据包的单次和二次数据包发射的情况，以及它们完全不存在的情况。进行数据分析时要考虑“双层”的影响，该双层代替了液体的聚结表面，并保留了由于将潜在的潜在表面能转换为其他形式（例如热能，压力扰动和能量）而引起的扰动的细小电流主动影响气体腔。一系列实验揭示了具有不同光谱成分的数据包的单次和二次数据包发射的情况，以及它们完全不存在的情况。进行数据分析时要考虑“双层”的影响，该双层代替了液体的聚结表面，并保留了由于将潜在的潜在表面能转换为其他形式（例如热能，压力扰动和能量）而引起的扰动的细小电流主动影响气体腔。一系列实验揭示了具有不同光谱成分的数据包的单次和二次数据包发射的情况，以及它们完全不存在的情况。进行数据分析时要考虑“双层”的影响，该双层代替了液体的聚结表面，并保留了由于将潜在的潜在表面能转换为其他形式（例如热能，压力扰动和能量）而引起的扰动的细小电流主动影响气体腔。