Bjerknes力与浮力耦合作用下水下爆炸气泡脉动载荷特性

安展逸¹，于福临^1,2*，吴凯伦¹，吕鹏伟¹，戴英东¹

1.山东交通学院船舶与港口工程学院，山东 威海  264209；2.威海市流固耦合动力学重点实验室，山东 威海  264209

摘要：为研究Bjerknes力与浮力耦合作用对水下爆炸气泡脉动载荷特性的影响，设计一种水下爆炸气泡产生与测量试验平台，通过气泡生成装置对水下铜电极加热产生气泡，采用高速摄影机记录气泡的脉动过程，采用压力传感器测量刚性壁面载荷压力。通过调节刚性壁面方位改变Bjerknes力方向，开展Bjerknes力与浮力方向相反和垂直2种工况下气泡脉动试验，分析无量纲参数γ对气泡脉动过程中形态变化、载荷特性及压力峰值变化的影响。试验结果表明：在Bjerknes力与浮力方向相反工况下，γ分别为0.7、1.0、1.3时，气泡在坍塌阶段分别呈锥状、梨状、球状；在Bjerknes力与浮力方向垂直工况下，γ分别为0.7、1.0、1.3时，气泡在坍塌阶段分别呈橄榄球状、锥状、水滴状；Bjerknes力与浮力方向相反或垂直时，气泡载荷压力峰值随γ增大均先增大后减小，γ=1.0时，气泡载荷压力峰值最大。γ相同时，Bjerknes力与浮力方向相反工况下气泡载荷压力峰值均高于Bjerknes力与浮力方向垂直工况，压力峰值差随γ增大先增大后减小，γ=1.0时，压力峰值差最大。

关键词：Bjerknes力；脉动载荷；水下爆炸气泡；浮力；无量纲参数

The pulsatile load characteristics of underwater explosion bubble under the coupled effect of Bjerknes force and buoyancy

AN Zhanyi¹, YU Fulin^1,2*, WU Kailun¹, LÜPengwei¹, DAI Yingdong¹

1. Naval Architecture and Port Engineering College, Shandong Jiaotong University, Weihai 264209, China;

2. Weihai Key Laboratory of Fluid-Structure Coupling Dynamics, Weihai 264209, China

Abstract: To investigate the coupled effects of Bjerknes force and buoyancy on the pulsatile load characteristics of underwater explosion bubble, an experimental platform for underwater explosion bubble generation and measurement is designed. Bubbles are generated by heating underwater copper electrodes through a bubble generation device, the bubble pulsation process is recorded using a high-speed camera, and the rigid wall load pressure is measured using pressure sensors. By adjusting the orientation of the rigid wall to change the direction of Bjerknes force, bubble pulsation experiments are conducted under two working conditions: Bjerknes force opposite to buoyancy direction and Bjerknes force perpendicular to buoyancy direction. The morphological changes, load characteristics, and pressure peak variation patterns during bubble pulsation are analyzed for different dimensionless distances γ. The experimental results show that under the condition where Bjerknes force is opposite to buoyancy direction, when γ is 0.7, 1.0, and 1.3 respectively, the bubbles exhibit conical, pear-shaped, and spherical structures during the collapse stage; under the condition where Bjerknes force is perpendicular to buoyancy direction, when γ is 0.7, 1.0, and 1.3 respectively, the bubbles exhibit football-shaped, conical, and water-droplet structures during the collapse stage; when Bjerknes force is opposite to or perpendicular to buoyancy direction, the bubble load pressure peak first increases and then decreases with increasingγ, reaching maximum at γ=1.0. Under the sameγcondition, the bubble load pressure peak when Bjerknes force is opposite to buoyancy direction is consistently higher than that when Bjerknes force is perpendicular to buoyancy direction, and the pressure peak difference value first increases and then decreases with increasingγ, reaching its maximum value at γ=1.0.

Keywords: Bjerknes force; pulsatile load; underwater explosion bubble; buoyancy; dimensionless distance