Fast Superfine Components and Sound Packets in Phenomena Induced by the Impact of a Drop on a Target Fluid in Quiescent Conditions

作     者：Yuli D.Chashechkin 

作者机构：Ishlinsky Institute for Problems in Mechanics RASMoscow119526Russia 

出 版 物：《Fluid Dynamics & Materials Processing》 (流体力学与材料加工（英文）)

年 卷 期：2020年第16卷第4期

页      面：773-800页

核心收录：

学科分类：080704[工学-流体机械及工程] 080103[工学-流体力学] 08[工学] 0807[工学-动力工程及工程热物理] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported by the Russian Science Foundation(Project 19-19-00598“Hydrodynamics and energetics of drops and droplet jets:formation motion break-up interaction with the contact surface”) 

主　　题：Liquid drop impact fine flow waves sound energy 

摘      要：The structure of the flow and the acoustic signals generated by the impact of a freely falling drop of water with an underlying quiescent fluid have been investigated for droplets having diameter 0.5 cm and a contact velocity in the range 1.5U5 m/*** experimental study has been supported by high-resolution videos of the flow(as seen from above and from the side).The evolution of ejecta,spikes,droplets spray,cavity,splash,secondary cavity,streamer,secondary droplets and sequence of capillary waves is reported *** particular,perturbations of the smoothed free surface with transverse dimensions from 0.03 cm to 0.15 cm have been observed in the center of the cavity and at the head of a growing *** total duration of the fine structure’s existence has been found to range from 30 to 50 *** acoustic packets have been recorded by means of a measuring hydrophone and a sensitive *** acoustic signals have revealed a high-frequency pulse associated with the primary contact and a delayed main lower-frequency packet(with a time shift ranging between 50 ms and 210 ms).The content of the acoustic signals indicates that from a large number of observed gas bubbles,only one was actually *** such a case(the formation of the bubble resulting from the break of a thin air bridge),the shock generated by the fast-moving remnant of the bridge produces volumetric oscillations of the *** sound stops as soon as the bubble takes a smooth elliptical or spherical *** details are reported about the relationship between the generation of capillary and acoustic waves and the features of hydrodynamic flows relating to the cavity,or the formation of a splash and the flows caused by the interaction of secondary drops with the perturbed surface of the target *** formation of fine flows components is associated with the release of available potential energy and the conservation of perturbations in a thin“double layerlocated in