Study on Load Characteristics of Underwater Explosion Using RKDG-LS-DGF and BEM

Abstract

This study numerically investigates the underwater explosion bubble dynamics during the process from detonation to bubble jet with a hybrid algorithm based on Runge Kutta Discontinuous Galerkin-Level Set-Direct Ghost Fluid method (RKDG-LS-DGF) and boundary element method (BEM). RKDG-LS-DGF method is used to simulate the physical process from the detonation of a column charge at one end to the formation of a nonspherical initial bubble and the process of bubble jet. And BEM is adopted to simulate bubble pulsing characteristics. In addition, the numerical results are compared with the experimental results to verify the feasibility of the numerical method. It is found that, during the detonation process of a column charge, the detonation product experiences a shape change from an initial ellipsoid into a sphere during expansion. After the detonation, the bubble experiences expansion and contraction and develops a jet. The jet threads through the bubble in the opposite direction to gravity and induces a high-pressure region. Subsequently, the pressure of this region decreases when the bubble reexpands after being penetrated by the jet. The numerical results agree well with the experimental data, which proves that axisymmetric RKDG-LS-DGF method and BEM are successfully combined to simulate the whole process of underwater explosion.

Attenuation of hole wall pressure and the prediction model for crack length in the scenario of blasting with water-coupled medium

“…Assuming that the blasting medium is a continuity elastic medium and the deformation is continuous process, and the displacement is only discontinuous at the crack, the pressure p of explosive gas is approximately uniformly distributed along the direction of crack length, and the frictional resistance of explosive gas in the shifting process is neglected. However, in the course of blasting and crushing, the water medium has some impact on the peak pressure of stress wave (Wang et al, 2017), so let the pressure p of explosive equalize the blasthole pressure p ( t ) of blasting with water-coupled medium. Denote the initial length of radial crack generated under the action of stress wave as L 0 and the total length of crack growth driven by explosive gas as L ( t ) .…”

High order WENO and DG methods for time-dependent convection-dominated PDEs: A brief survey of several recent developments

“…We list below only a few examples over the past year (since 2015). Recent applications of DG methods can be found in the simulations of the Cahn-Hilliard-Brinkman system [85], compressible flow in the transonic axial compressor [190], computational astrophysics [197], computational geosciences [221], elastodynamics [53], flow instabilities [51], Fokker-Planck equations [152], fractional PDEs [111,243], front propagation with obstacles [17], functionalized Cahn-Hilliard equation [87], interfaces [278], magnetohy-drodynamics [265], moment closures for kinetic equations [2], multi-phase flow and phase transition [52,169], Navier-Stokes and Boussinesq equations [64,224], nonlinear Schrodinger equation [86,149,158], ocean waves [192], population models [112], porous media [84], rarefied gas [212], semiconductor device simulation [155], shallow water equations [73], thin film epitaxy problem [247], traffic flow and networks [21], three-dimensional flows [175], turbulent flows [246], underwater explosion [235], viscous surface wave [245], and wavefield modeling [95]. This very incomplete list over just one year period clearly demonstrates the wide-spread application of the DG method in computational science and engineering.…”