The Keeping Volume Fraction Of Fluids Invariable Methods For Reconstructions Of Moving-Interfaces Based On VOF Methods

In rectangular meshes, the keeping volume fraction of fluids invariable method is presented for reconstruction of moving-interfaces, based on the VOF method, and is studied as follows.This method can approximate moving interfaces by a diagonal line in a single grid, and points of the intersection of diagonal lines and the public sides between the adjacent grids coincide. According to keep the volume fraction invariable in each mesh, the nonlinear algebraic equations are built in surface meshes. By solving the equations, the position of the intersection of moving-interfaces and the grid lines are determined, so the shape and location of moving interfaces are simulated.It provides two methods, the steepest descent algorithm and the direct method, to solve the established equations. The steepest descent algorithm can accurately simulate moving interfaces and be applied to the large grids computing. Based on the research of the established nonlinear algebraic equations in the keeping volume fraction of fluids invariable method, the unified expression of equations is inferred and the direct method is proposed. On the condition of solution of the direct method existed, the solution is very accurate, and the computing speed of the direct method is very fast to handle large grids computing. And it is further to discuss well-posedness of the solution by the direct method. To improve the keeping volume fraction of fluids invariable method, it is promoted to solve the simulation of many closed interfaces and open interfaces.