Foam flow around an obstacle: Simulations of obstacle-wall interaction

The flow of a two-dimensional foam around an obstacle provides a benchmark experiment in which to study the transition from discrete to continuous properties of this complex fluid. The interaction between the obstacle and the walls of the channel is simulated using the Surface Evolver. The lift and drag forces on a circular obstacle are measured and the contributions to the total force of the film network and the bubble pressures are assessed. As the distance of the obstacle from the wall decreases, the lift force is found to increase significantly whereas the drag force does not vary greatly.