Interaction of Radial and Forward Pulses of Cavitation Bubbles
I.Margulis (Department of Sonochemistry, N.N. Andreyev Acoustics Institute, Moscow, Russia)
In the work we consider main reasons of bubble's forward motion and influence of forward motion on bubble dynamics. We obtained a new system of equations that described bubble.s radial and forward motion. Calculations were carried out for two types of acoustic field: standing and progressive sinusoidal sound waves. At fast collapse the effective transmitting of radial energy into forward one takes place. Forward motion damps adiabatic collapse considerably, usually forward motion decreases Tmax in 4 times (to 2800 K) and maximum of r in 4 times (to 140 m.s-1). So, if heat exchange, lose of sphericity, interaction with other bubbles and flows of liquid are taken into consideration additionally, in the field of progressive sound waves Tmax <= 1000 K. While one observes smooth forward motion of cavitation bubbles, they jump for every fast collapse and stay immovably during remaining time. Maximum of u (at fast collapse) reaches several hundreds of m.s-1. A mean per a period u is calculated to be 1.5 m.s-1 corresponds to experimental data.
Section : 11