An Application And Study Of Level Set Method In Multi-material Flows

Level Set Method using the Level Set function to keep track of the interfacemotion, automatically handles the interface that undergoes topological changes, the briefmethod has another advantage of handling the large deformation problem easily. The zerolevel of Level Set function is the interface of two fluids, the other level value of Level Setfunction of points around interface is the signed distance to interface, and Level Setfunction with different sign would represent different fluid. Ghost Fluid Method usingLevel Set function separates the one fluid field contains two fluids, each field whichconsists of real field and ghost field can be calculated. Then the method successfullyavoids the problem that different fluids with different equations of state.The Level Set method on unstructured grid is used to simulate multi-material flowproblems. Euler equation is solved by finite volume method with HLLC (Hartern, Lax,van Leer, Contact) approximate Riemann method computing the flux of control face. LevelSet equation is also solved by finite volume method with Lax-Friedchs method computingthe flux. Narrow Band method is used to reduce computational costs. Re-initialization iscompleted by Fast Marching Method. The method treating interface is Ghost Fluid Method.Two-stage Runge-Kutta time integration scheme can achieve second order time accuracy.The space accuracy is also second order. The single phase fluid shocktube problem,Sodshocktube problem, and gas/water shocktube problem are considered here, The numericalresults agree with the exact solution; Air interacting with helium bubble,air interactingwith R22, and Ritchmyer-Meshkov instability problem are also simulated, The results aresatisfied; The results were obtained on moving shock interacting with bubbles includingthe bubbles evolution.