Numerical Simulation Of The Viscous Flow Over The Submarine And Method Research On Predicting Its Vsicous Resistance

The characteristics of the flow, especially wake flow around a submarine, not only have a direct effect on the hydrodynamic performance of the submarine, but also are the main source of the hydrodynamic noises of the submarine. An effective numerical simulation method to predict the characteristics of the flow is a very important research problem in the ship hydrodynamics.The flow over a revolution body is a classical problem in the CFD. So simulating the flow over a revolution body can be used to validate the numerical computational program. Numerical simulations of the three dimension viscous flow over the SUBOFF-1 model provided by DARPA and other two models are processed by solving RANS equations withκ-εtwo-equation turbulence model and finite volume method (FVM), and with SIMPLEC method for pressure-linked terms, central difference shemes for temporal derivative terms, and second-order upwind schemes for convective and diffusive terms. Computational results of this paper are very consistent with test data, even more close to the test data by the computational results provided by some references. It shows numerical simulation method in this paper is available.Then, numerical simulation of the three-dimensional viscous flow over the SUBOFF–8 submarine model with full appendages provided by DARPA is processed. A so-called near-wall model, namely enhanced wall functions combined a two-layer turbulence model is applied to enable the near-wall region to be solved with a finer mesh, which is all way to the wall, including the viscous sub-layer. Wake velocities at the propeller disk plane, other than pressure coefficient and skin friction coefficient, are given, and vortices structures shed from the fairwater and four stern appendages are observed from the velocity vectors. Computational results of this paper are very consistent with test data, and exceed the computational results given by some references.A mathematical model of the revolution body satisfied the main sizes and equilibrium condition of submarines is presented in this paper, which can create the hull form and offsets automatically. Lots of towing tank test data are used to prove the validity of the numerical simulation method in this paper to predict the viscous resistance of a submarine under water. By simulating the flows over a series of submarine models, which are created by our mathematical method through changing the parameters of hull form, the viscous resistances of these submarine models can be predicted, so"submarine viscous resistance numerical test tank"can be founded.Besides, the modified computational viscous resistance and towing tank test data are used to train BP neural network with Levenberg-Marguardt and Bayes regularization arithmetic. By this way conventional submarine viscous resistance numerical atlas can be created and the resistance can be estimated very rapidly. Mininum resistance submarine form can be designed with the method in submarine concept design.