Abstract

Air lubrication systems for underwater applications have gained great popularity in recent years. Large bubbles, around We ≥ 100, show a large area of drag reduction than a small and microbubble, especially for large scale flow problems such as ship surface. However, it is hard to maintain their shape and prone to deform in a turbulent flow. In order to understand and control the drag reduction mechanism by the large bubble injection, it is necessary to know the behavior of large bubbles in the turbulent boundary layer and their interaction with the skin friction. In this study, a solver “interIsoFoam” for two-phase flow of an open-license software “OpenFOAM” is applied for an LES of turbulent channel flow with a large bubble, the gas-liquid interface of which is directly captured by improved VOF method. In a recent publication [1], we presented the numerical procedure of how to inject the large bubble on turbulent channel flow. The research objectives in this study are investigation on flow change of the horizontal channel flow included large bubble. From this observation, understanding large bubbles characteristic such as the surrounding flow phenomena was observed.