Numerical Study on the Bifurcation Mechanism of Air Layer on a Flat Plate

초록

There is no need to emphasize the importance of the frictional resistance of ships to both naval architecture and ship owners because it is known that frictional resistance takes about 70 percent of the total resistance of most merchant ships. Therefore, the development of air lubrication system for ships has been pursued to save fuel costs by reducing the frictional resistance. The air layer is diffused and bifurcated due to the interaction between water and air layer. In this study, the diffusion angle and pattern of air layer generated on the surface of a flat plate were investigated numerically using CFD. Before the simulations, grid resolution test was performed to evaluate the sensitivity of the grid. Air diffusion angle and pattern according to the variation of the water inflow velocity and air injection speed were compared with experimental data and the diffusion patterns of air layer were investigated through the velocity contour and vector as well as vorticity contour to explain the bifurcation mechanism of air layer.