SHOCK-WAVES IN A LIQUID CONTAINING SMALL GAS-BUBBLES

Numerical and experimental studies of the transient shock wave phenome na. in a liquid containing non-condensable gas bubbles are presented. In the numerical analysis, individual bubbles are tracked to estimate the effect of volume oscillations on the wave phenomena. Thermal proce sses inside each bubble, which have significant influence on the volum e oscillation, are calculated directly using full equations for mass, momentum and energy conservation, and those results are combined with the averaged conservation equations of the bubbly mixture to simulate the propagation of the shock wave. A silicone oil/nitrogen bubble mixt ure, in which the initial bubble radius is about 0.6 mm and the gas vo lume fraction is 0.15% - 0.4%, is used in the shock tube experiments. The inner diameter of the shock tube is chosen to be 18 mm and 52 mm i n order to investigate the multidimensional effects on the wave phenom ena. In a fairly uniform bubbly mixture, the experimental results agre e well with the numerical ones computed using a uniform spatial distri bution of bubbles. On the other hand, in all the other experiments, th e bubbles in the shock tubes are not distributed uniformly, being rela tively concentrated along the axis of the tube. This non-uniformity su bstantially alters the profile of the shock waves. The numerical predi ctions where such a distribution is taken into account agree well with those experimental data. (C) 1996 American Institute of Physics.