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

AN Zhanyi; YU Fulin; WU Kailun; LÜ Pengwei; DAI Yingdong

doi:10.3969/j.issn.1672-0032.2026.01.012

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 increasing γ,reaching maximum at γ=1.0.Under the same γ condition,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 increasing γ,reaching its maximum value at γ=1.0.