A High-precision Central Lagrangian Method Based On Characteristic Theory For Simulating The Detonation Of Condensed Explosives

Detonation plays an important role in the development of defense technology and industry production.Compared with gaseous detonation,condensed explosive detonation has higher detonation pressure,velocity and energy density.Accordingly,the development of numerical methods for condensed explosive detonation with high confidence is of great importance.Based on characteristic theory,we proposed a second-order cell-centered Lagrangian scheme for computing the condensed explosive detonation problem.The detonation equations are discrete in the framework of cell-centered Lagrangian scheme and finite volume method.Then we use characteristic properties of control equations to solve the velocity and pressure of mesh nodes,and these physical variables are used to update grid node locations and to calculate the numerical flux.The physical variables obtained by characteristic theory are simple but take fully account of multidimensional effect.The method is a generalization of 1D Godunov scheme in multi-dimensional problems.In order to achieve high order accuracy,we use second order semi-implicit Runge-Kutta method to compute time integration and piecewise linear reconstruction with gradient limiter to calculate variables in the corner.In this paper,we use ignition growth detonation model with three terms Ignition-Growth reaction rate function and JWL equations of state to simulate condensed explosive detonation.Results of simulations show that the calculation method has good conservation and resolution,can accurately describe the propagation process of detonation waves and flow rules in reaction zone,and can also reflect the image of 2D detonation wave interaction.