双空泡溃灭及空化噪声的建模

空泡溃灭时会产生很大的瞬时压强,造成流体机械装置的空蚀破坏并产生噪声和剧烈振动。为研究双空泡溃灭及溃灭时声辐射的规律,忽略流体的压缩性,建立了双空泡的运动方程。在L igh th ill方程基础上建立了双空泡溃灭时流体中的声辐射模型,并进行了数值计算。计算结果表明:随着空泡间距的减小,空泡溃灭的最小半径减小,溃灭时间延长,空泡辐射声压增大,说明空泡间的相互作用使空泡的溃灭过程变缓并使空泡辐射的噪声增强。

Noise generation during the simultaneous collapse of two bubbles

Bubble collapse causes large transient pressures resulting in cavitation erosion of fluid mechanical equrpment,noise,and vibrations.A dynamic model was developed for a two-bubble system which neglects fluid compressibility to analyze two-bubble collapses and cavity noise generation.The acoustic radiation in the fluid was numerically calculated using a Lighthill equation based model for the two-bubble collapse.The calculational results show that the minimum bubble collapse radius decreases and that the collapse time and cavity noise pressure increases with decreasing distance between the two bubbles,which indicates that bubble interactions reduce the collapse speed but increase the radiated noise.