水中高压脉动气泡与浮体流固耦合特性研究  

FLUID-STRUCTURE INTERACTION BETWEEN A HIGH-PRESSURE PULSATING BUBBLE AND A FLOATING STRUCTURE

作　　者：胡振宇 曹卓尔 李帅[1] 张阿漫[1] Hu Zhenyu;Cao Zhuoer;Li Shuai;Zhang Aman(College of Shipbuilding,Harbin Engineering University,Harbin 150001,China)

机构地区：[1]哈尔滨工程大学船舶工程学院,哈尔滨150001

出　　处：《力学学报》2021年第4期944-961,共18页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(51709056,51979049);中央高校基本业务费(3072020CFJ0105);黑龙江省博士后科研启动金(LBH-Q20016)资助项目。

摘　　要：本文针对水中放电气泡与水面浮体流固耦合作用开展实验和数值研究,采用边界积分法对气泡运动进行数值模拟,利用辅助函数法提高非线性流固耦合问题的计算精度,同时运用双节点法保证气-液-固三相交界线的计算稳定性.实验中,采用水下放电技术生成气泡,使用高速摄影捕捉气泡动力学行为与浮体运动响应.首先对比数值与实验结果,二者吻合良好,验证了数值计算模型的有效性和正确性.然后通过对气泡与浮体的无量纲距离γs(气泡最大半径为特征长度)进行系统研究发现:(1)γs从0.2增大至2时,气泡在坍塌阶段分别形成了颈缩型环状射流(0.2≤γs≤0.3)、接触射流(0.4≤γs≤0.6)、非接触射流(0.7≤γs≤1)、对射流(1.1≤γs≤1.3)和反射流(1.4≤γs≤2)等5种典型射流模式;(2)正射流速度随γs先增大后减小再增大,并且当0.7≤γs≤0.9时,速度可达约1000 m/s;反射流速度随γs增大而增大;(3)在本文实验条件下,γs<1.5时浮体对气泡的Bjerknes吸引力强于自由液面的Bjerknes排斥力导致气泡在坍塌阶段向浮体迁移;当γs≥1.5时自由液面对气泡的排斥作用更强,气泡在坍塌阶段远离自由液面.This paper experimentally and numerically investigates the fluid-structure interaction between a spark-induced bubble and a floating structure. The boundary integral method is adopted to simulate the bubble dynamic behaviors and the auxiliary function method is used to improve the computational accuracy of the nonlinear fluid-structure interaction. The double-node method is employed to maintain the computational stability of the gas-liquid-solid interaction line. Besides,we use the underwater electric discharge technique to generate bubbles and the high-speed photography to record the bubble dynamics and the structural responses. Firstly, we compare the numerical result with the experimental data and favorable agreement is achieved which validates this numerical model. Through parametric study with respect to the dimensionless distance γsfrom the initial bubble center to the floating structure(the reference length is the maximum bubble radius), we then find that(1) as γsincreases from 0.2 to 2, five types of jetting pattern such as necking together with annular jet(0.2≤γs≤0.3), contacting jet(0.4≤γs≤0.6), non-contacting jet(0.7≤γs≤1), collision of a jet directed towards the floating body and a counter-jet(1.1≤γs≤1.3) and individual counter-jet(1.4≤γs≤2) can be formed;(2) it is also found that the velocity of the jet directed towards the structure first increases, then decreases and finally increases again as γsincreases;additionally, it may be in the order of ~1000 m/s when γsvaries from 0.7 to 0.9;as γsincreases, the counter-jet velocity increases;(3) under the conditions of the presented experiments, the bubble migrates towards the floating structure when γs<1.5 due to the stronger Bjerknes attraction of the floating structure than the Bjerknes repellence of the free surface on the bubble during the collapsing phase. When γs≥1.5, however, the free surface has stronger effects on the migratory behavior of the bubble than the floating structure which causes the bubble to migrate

关 键 词：气泡 流固耦合 浮体 边界积分法 高速摄影 

分 类 号：O35[理学—流体力学]