Three-dimensional high order large-scale numerical investigation on the air explosion

Based on the double shockwave approximation procedure and combining the real ghost fluid method (RGFM) with the level-set method, a local Riemann problem for strongly nonlinear equations of state such as the JWL equation of state is constructed, which has suppressed successfully the numerical oscillation caused by high-density ratio and high-pressure ratio across the interface between the explosion products and the air. A fifth order finite difference weighted essentially non-oscillatory (WENO) scheme and a third order TVD Runge-Kutta method are utilized for spatial discretization and time advance, respectively. A fully enclosed type MPI-based parallel methodology for the RGFM procedure on a uniform structured mesh is presented to realize the parallelization of the three-dimensional RGFM-based code for the air explosion. The overall process of the three-dimensional air explosions of both TNT and aluminized explosives has been successfully simulated. The overpressure at different locations of the three-dimensional air explosions for both explosives mentioned above is monitored and analyzed for revealing the influence of the aluminum powder combustion on the overpressure of the explosion wave. The numerical results indicate that, due to the aluminum powder afterburning, the attenuation of the explosion wave formed by the aluminized explosives is slower than that caused by TNT.