Numerical Simulation Of Some Hydrodynamic Forces For Submerged Body Advancing Near Free Surface

Compared with the deep water submerged body, the flow field around a moving submerged body near the free surface is more complex, and the influence of the free surface can't be ignored. The flow field around the advancing submerged body has been studied experimentally before in this university, the test cost was high and time needed was long. And we need a more economic approach to obtain the results. Along with the fast development of the computer hardware and computational fluid dynamics in recent years, some numerical methods have been developed which can be used to calculate the flow field around the submerged body. Numerical methods are economic in both cost and time, and they can estimate some aspects which the experiments are hard to deal with, In this thesis, the fluid flow with free surface and some hydrodynamic forces due to an ellipsoid and a submarine moving at constant speed are simulated with the CFD software FLUENT.First, the flow fields of the ellipsoid near free surface in different submergences and the same other conditions are simulated with FLUENT. The influences of different submergences on free surface, resistance, lift and motion of the body can be obtained. The simulation resistance with the software FLUENT is compared with that by a mature semi-empirical method based on potential theory.In the simulation of the flow field around a submarine, the submarine is attached with appendages such as bridge and fins. The influences of the submergences on free surface, resistant coefficient, lift and motion due to the horizontally traveling submarine can be obtained, and the comparison of the calculated results of the ellipsoid with that of the submarine is presented.