Bubble Behavior at an Uneven Wall

The present study deals with single bubble growth on an uneven wall. A model problem is defined and solved using a three-dimensional numerical simulation. The wall has the shape of a triangular cavity and feature vortices. The equations solved in the present study are based on macro region modelling of the bubble alone and describe its growth from the initial state to detachment from the surface and consequent motion. The model includes a simultaneous solution of conservation equations for the liquid and gaseous phases, in conjunction with three-dimensional interface tracking. The latter is achieved using the level-set method. The numerical modeling includes the multi-grid method. The complete three-dimensional model is discretized using an original in-house numerical code realized in MATLAB. Different cases of bubble growth on the triangular cavity walls are investigated. The main conclusion from the calculations is that the bubble shape and its growth rate strongly depend on its location and on the channel orientation. New features, not possible for flat walls and special for this case, are revealed and discussed. It is demonstrated that under certain conditions, the bubble is obstructed by the surface geometry. It is also shown how a growing bubble affects the flow field inside a cavity, interacting with the vortex structure.