| Summary: | 碩士 === 國防大學中正理工學院 === 造船工程研究所 === 92 === It is always to take a long time to perform the numerical simulation of an underwater vehicle motion involving the free surface and viscous effects. The cumbersome numerical computation for the flow field analysis of a complex geometry sometimes hesitates the researchers and degrades the practicality of the numerical method.
In order to speed up the numerical computation, the zonal approach is accepted to probe the flow field around the underwater vehicles in this thesis. The computational domain is divided into two main regions, which include the viscous and invicid zones respectively. The viscous zone covers the region near the underwater vehicle. The boundary layer equation and the RANS equations are employed to resolve the viscous effect near the body. On the other hand, the Laplace equation is applied in the invicid zone to obtain a potential flow solution, which will be used as a boundary condition for the viscous flow computation outer the viscous zone. Since the zonal approach could speed up the convergence of the RANS computation, such method could reduce the computational time by large when compared with other numerical methods.
The computation results of the resistance coefficients for a torpedo-typed body from the zonal approach are in close agreement with the results from the experimental formula published in ITTC. The work in this thesis has provided a basis for the flow field simulation around the marine vehicle. The present numerical methods can be extended to account for a complicated geometrical body such as submarine motion under the water to enhance the design capability of an underwater vehicle in Taiwan.
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