Numerical Study Of Hydrodynamic Forces On A Maneuvering Submarine

The developmet and utilization of marine resources ask for higher demand on maneuvering of underwater vehicle, therefore, it is necessary to study numerical prediction method on hydrodynamic derivatives of underwater vehicle. Because submarine named SUBOFF has the most comprehensive test date, becoming the standard computational example of verifying numerical method, so this paper studies numerical method on maneuvering of this submarine using FLUENT software,Firstly, the numerical simulation of direct test is conducted for a submarine named SUBOFF in this paper. By simulating for direct test of bare submarine, the influences of fluid materials and temperature on numerical computational results are analyzed, which show that when the temperature raise three centigrade, the computational results will decrease about one per cent; In the same temperature the results in seawater material are bigger than about three per cent in freshwater materials. Therefore, selecting the same temperature material as fluid material in test is an important step in numerical simulation.By simulating for direct tests of bare submarine and submarine with fully appendages, the applications of Standardκ-ωand RNGκ-ωturbulence models are analyzed. By comparing with the numerical results with experiment date, we can see that: Standardκ-ωmodel is more suitable than RNGκ-ωmodel for numerical simulation of bare submarine; RNGκ-ωmodel is more suitable than Standardκ-ωmodel for numerical simulation of submarine with fully appendages. This conclusion has the guiding significance for numerical simulation of towing test. The reliability of meshing and numerical method by numerical simulation for direct test, laying the good foundation of simulation for towing test and rotating arm test.Secondly, numerical simulation for towing test of submarine is conducted in this paper. The influences of Standardκ-ωand RNGκ-ωturbulence models for 4.5kn and 6.5 kn speeds on computational results are analyzed, which show that:the simulation results of 4.5 knots is better than 6.5 knots speed; the simulation results of Standardκ-ωturbulence model is better than RNGκ-ωin towing test of bare submarine, the conclusion of application of turbulence models is validated. The errors of velocity hydrodynamic derivatives of bare submarine are lower than 8 per cent in 4.5 knots using Standardκ-ωmodel.Numerical simulations of towing test of B.H. + Sail and B.H. + 4 Planes are conducted in 4.5 knots using RNGκ-ωmodel. The resistance, the lateral force and yaw moment at different drift angles are predicted. By comparing computational results with experiment results, we can see that: the errors of velocity hydrodynamic derivatives of B.H. + Sail are lower than 8 per cent, good meeting the requirements of engineering predication; the errors of velocity hydrodynamic derivatives of B.H. + 4 Planes are lower than 11 per cent, meeting the requirements of engineering predication.Thirdly, numerical simulation for rotating arm test of bare submarine is conducted by SRF method. The computational results show that the error of yaw moment rotating derivative is 52.5%, engineering forecast accuracy is lower.Finally, numerical simulation for rotating arm test of submarine is conducted by an added momentum source method, based on structured grid. The hydrodynamic forces and moments at different angular velocities are predicted, the lateral force and yaw moment at different drift angles are predicted. By comparing with the experiment dates, which show that the errors of rotating derivative of bare submarine and submarine with appendages are lower than 9 per cent, meeting the requirements of engineering predication.