SHOCK-WAVES IN A UNIFORM BUBBLY FLOW

An experimental and numerical study of transient shock wave phenomena in a liquid containing noncondensable gas bubbles is presented. Experi ments are done in a shock tube with an upwardly directed bubbly flow t o obtain a uniform spatial distribution of bubbles. The bubbly flow ha s an initial gas volume fraction of 0.2%. The bubbles have a radius of 0.6 mm. The liquid used is a silicone oil whose kinematic viscosity i s 50 x 10(-6) m(2)/s. Nitrogen and SF6 gas bubbles are tested to bring out the thermal effects of the bubble interior. The numerical calcula tion is performed using a modified mathematical model based on Kameda and Matsumoto [Phys. Fluids 8, 322 (1996)]. The transient pressure pro files determined in the experiment for the upwardly bubbly flow agree well quantitatively with those obtained by the numerical calculation u sing a uniform spatial distribution of bubbles. The SF6 experiment sho ws that the radial motion of the bubbles should be estimated by solvin g an equation in which the liquid compressibility is taken into accoun t. (C) 1998 American Institute of Physics.