| In a complex domain, three dimensional computations were carried out to study moving shock interacted with gas-water interface and bubble expansion underwater at high pressure and temperature. Based on concept of MGFM (modified ghost fluid method) and RGFM (real ghost fluid method), an approximate Riemann problem was constructed to describe gas-water interface condition with strong discontinuity initially. Level set method was used to track the moving interfaces. Following topics were included in this thesis:(1) A strong moving shock interacted with bubbles underwater.(2) Bubble expansion underwater at high pressure and temperature, such as cylindrical, spherical and V-shaped conical bubbles.(3) Paralleled computation on bubble expansion at high pressure and temperature based on multi-block method.Some works are summarized as follows:(1) Brief introduction, related progress on flow interface especially on gas-water and works in this thesis were presented in chapter 1.(2) In chapter 2, governing equations of flow field, level set method and extrapolated variables were respectively illustrated in Cartesian and body fitted coordinate frames. Meanwhile, MGFM (modified ghost fluid method) and RGFM (real ghost fluid method) approaches are adopted to describe gas-water interface conditions.(3) In chapter 3, second order TVD and fifth order WENO schemes were respectively introduced to solve Eulerian equations, level set and reinitialized equations for flow-field and gas-water interfaces. Also, parallel and multi-block methods were introduced briefly based on OPENMP methodology.(4) In chapter 4, benchmark examples and numerical results were discussed on shock interaction with gas-water interface and expansion of bubble underwater at high pressure and temperature. Ten examples were carried out and analyzed in this chapter to show highly resolved gas-water interfaces.(5) In chapter 5, some conclusions and future works were presented in this thesis.
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