2d Gel Coupling Method And The Numerical Simulation Of The Explosion Container

In the numerical simulation of multi-material hydrodynamics, Eulerian and Lagrangian methods have their own advantages and limitations. One of important fields is how to effectively use their respective advantages in the multi-material hydrodynamic calculations. MF PPM (Piecewise-Parabolic Method) Code based on Euler method and DEFEL (2-D Finite Elements Code) based on Lagrange method were coupled according to the pressure and normal velocity consecutive rule. GEL (Ghost-fluid Euler-Lagrange) method was developed. This method has the advantage of performing large deformation fluid field while small deformation shell, complicated flow and interactions of many objects. 2-D example was simulated and compared with the results in reference to prove the validity of the coupling program. Simulation on global and ellipsoidal explosion container got consistent results with experiments, which proved this code was valid to simulate the flow structure loaded by a blast wave from a central charge.The main points of this work are as follows:1. Based on a finite difference Euler code (PPM method) and a 2-D finite element Code (DEFEL), a two-dimensional code, which can couple the Euler calculations and Lagrange calculations, has been developed in this paper. An one-dimensional Riemann problem test and a two-dimensional test for moving boundaries (so-called cylinder lift-off problem), which are designed to measure the accuracy of the coupling method, are presented in the paper. The two-dimensional results using GEL method is also consistent with the results from the literature, thus validating the feasibility of GEL method used in the paper.2. Numerical results are obtained by applying the validated codes to simulate the typical tests. It was shown that our codes have successfully solved the problem of explosion products expansion to air. The given figures have clearly shown the ignition and detonation growth, the blast wave propagation, the fluid structure interaction processes and the deformation of structures, etc. The results are also in consistent with the experimental data reported.3. Chapter 6 gives other applications of GEL coupling method, including the problem of explosion under water,which involved the multi-fluid and multi-objects interaction; the problem of gas action on the projectile-sabot model and the problem of the interaction of stell shell ball and gas. 4. Conclusions and suggestions to the future work are given in the final chapter of this paper.