The effects of non-physical mixing on interface development are still not reasonably evaluated when diffuse interface methods(DIMs)are employed to treat the two-medium flows with immiscible interfaces,especially for c...The effects of non-physical mixing on interface development are still not reasonably evaluated when diffuse interface methods(DIMs)are employed to treat the two-medium flows with immiscible interfaces,especially for compressible multimedium flows with geometrical source terms.In this work,we simulate radially symmetric multi-medium flows employing the sharp interface methods(SIMs)and DIMs to evaluate their performance such as pressure dislocations,mass conservation,and convergence.The g-based model and the five-equation transport model are two common DIMs,which are extended to equations with geometrical source terms combined with discontinuous Galerkin(DG)methods.For the SIMs,we employ the classical modified ghost fluid method(MGFM)and its second-order extension(2nd-MGFM)developed recently.Numerical results exhibit that the 2nd-MGFM is more effective in maintaining the interfacial pressure equilibrium relative to the MGFM.The DIMs can always maintain the pressure continuity naturally and total mass conservation,which is not available for SIMs.Further,under the premise of immiscible interfaces defined artificially,the DIMs cannot provide satisfactory single medium mass conservation,while the SIMs have a smaller mass error.In addition,compared to the other three methods,the 2nd-MGFM has higher confidence for radially symmetric flows,matching the exact solution in sparser grids.展开更多
We propose a hybrid scheme combing the diffuse interface method and the material point method to simulate the complex interactions between the multiphase compressible flow and elastoplastic solid.The multiphase flow i...We propose a hybrid scheme combing the diffuse interface method and the material point method to simulate the complex interactions between the multiphase compressible flow and elastoplastic solid.The multiphase flow is modelled by the multi-component model and solved using a generalized Godunov method in the Eulerian grids,while the elastoplastic solid is solved by the classical material point method in a combination of Lagrangian particles and Eulerian background grids.In order to facilitate the simulation of fluid-solid interactions,the solid variables are further interpolated to the cell center and coexist with the fluid in the same cell.An instantaneous relaxation procedure of velocity and pressure is adopted to simulate the momentum and energy transfers between various materials,and to keep the system within a tightly coupled interaction.Several numerical examples,including shock tube problem,gasbubble problem,air blast,underwater explosion and high speed impact applications are presented to validate the numerical scheme.展开更多
基金supported under the National Natural Science Foundation of China(No.12101029)the Postdoctoral Fellowship Program of CPSF under Grant(No.GZC20233380).
文摘The effects of non-physical mixing on interface development are still not reasonably evaluated when diffuse interface methods(DIMs)are employed to treat the two-medium flows with immiscible interfaces,especially for compressible multimedium flows with geometrical source terms.In this work,we simulate radially symmetric multi-medium flows employing the sharp interface methods(SIMs)and DIMs to evaluate their performance such as pressure dislocations,mass conservation,and convergence.The g-based model and the five-equation transport model are two common DIMs,which are extended to equations with geometrical source terms combined with discontinuous Galerkin(DG)methods.For the SIMs,we employ the classical modified ghost fluid method(MGFM)and its second-order extension(2nd-MGFM)developed recently.Numerical results exhibit that the 2nd-MGFM is more effective in maintaining the interfacial pressure equilibrium relative to the MGFM.The DIMs can always maintain the pressure continuity naturally and total mass conservation,which is not available for SIMs.Further,under the premise of immiscible interfaces defined artificially,the DIMs cannot provide satisfactory single medium mass conservation,while the SIMs have a smaller mass error.In addition,compared to the other three methods,the 2nd-MGFM has higher confidence for radially symmetric flows,matching the exact solution in sparser grids.
文摘We propose a hybrid scheme combing the diffuse interface method and the material point method to simulate the complex interactions between the multiphase compressible flow and elastoplastic solid.The multiphase flow is modelled by the multi-component model and solved using a generalized Godunov method in the Eulerian grids,while the elastoplastic solid is solved by the classical material point method in a combination of Lagrangian particles and Eulerian background grids.In order to facilitate the simulation of fluid-solid interactions,the solid variables are further interpolated to the cell center and coexist with the fluid in the same cell.An instantaneous relaxation procedure of velocity and pressure is adopted to simulate the momentum and energy transfers between various materials,and to keep the system within a tightly coupled interaction.Several numerical examples,including shock tube problem,gasbubble problem,air blast,underwater explosion and high speed impact applications are presented to validate the numerical scheme.
