Numerical Simulation On Bubbly Ship Wake

Ship bubbly wake is a streak of foamy and turbulent region behind a moving ship, which is the special production of ship's movements. The study on ship wake's characteristics and application has been a hot field for years in the international marine science and engineering. Compared with the other flow field, the bubbly wake area is special due to all of its features, and contains abundant information about the objective ship, which makes it be of very important military research and application value. Besides, its civil use has been explored gradually.In this paper, a numerical method to simulate the bubbly wake of a CFD benchmark ship model is presented based on the general CFD code FLUENT, after the current progress of bubbly wake research in the world is systematically reviewed and summarized. The main resolution processes are as followed: Firstly, the viscous flow with free surface around a ship model is numerically simulated based on the VOF two-phase model; then after the predicted free surface is fixed throughout the computation with a rigid-lid-free-surface method, the under-water flow field is computed based on the Mixture multiphase model to simulate the bubbly wake around the hull. In the simulating process, the SIMPLE algorithm (Semi-Implicit Method for Pressure-Linked Equations) is applied. Besides, the Realizable k-εtwo-equation turbulent model and Reynolds Stress Model are used to analysis the effects of turbulence model on the bubbly ship wake.Based on the work mentioned above, the ship bubbly wake is computed for some more times on different conditions by adopting body force model to simulate the rotational movements of the propeller, selecting different uniform bubble sizes, and varying the ship speed. Then the influences of them on the simulation are discussed accordingly. The air entrainment model used here and the solving procedure put forward in this paper are justified by the qualitatively reasonable computed results.