Bubbles in front of a solid boundary
Prof Werner Lauterborn (University of Gottingen, GE)
Bubbles near solid boundaries are interesting objects because of their erosion and cleaning potential. The scientific approach to describe and build up an understanding for bubble action on solid surfaces is reviewed and discussed up to the latest developments. Experimentally, the highest-speed photographic instrumentation is needed to capture the fast dynamics of bubble shape—in particular liquid jet formation—and shock wave propagation. On the theoretical-numerical side, the respective bubble models have to be formulated and solved. Because of the complicated dynamics recourse has to be made to the Navier-Stokes equations with appropriate boundary conditions. Their numerical solution requires high-speed computation facilities and appropriate software. Results on bubble shape dynamics with jet formation and shock wave emission obtained with the help of the open source software package OpenFOAM is reported for bubbles expanding and collapsing at different distances from a flat solid boundary.