Numerical simulation of underwater explosion wave propagation in water-solid-air/water system using ghost fluid/solid method

摘要

The analysis of deformations of structures immersed in water due to explosion waves is important for off-shore oil and marine applications. A challenging issue in these problems is the satisfaction of continuity conditions at the fluid/structure interface. We numerically analyze these transient problems by using the ghost fluid/solid method, and coupling the isobaric fixing technique with the real ghost fluid method. We verify accuracy of the developed algorithm by comparing predictions from it with the analytical solution for a one-dimensional problem in which a plane wave traveling in water impinges upon a water/solid interface. We show that the coupled method has first order accuracy. Numerical results for the propagation of a spherical wave interacting with a fluid/solid interface computed with the developed method are found to compare well with those from the commercial software, ANSYS, that uses the arbitrary Eulerian-Lagrangian method. It is found that the intensity of the reflected tensile wave at a solid/water interface is less than that at a solid/air interface. Factors motivating this work include (i) using only the finite difference method for numerically solving equations governing transient deformations of fluids and solids that employs the ghost fluid/solid method to accurately satisfy continuity conditions at the fluid-solid interface, (ii) avoiding the need to refine the grid near the fluid-solid interface, and (iii) having an in-house capability of modeling detonation of a charge and study the interaction of the shock wave produced with the deformable structure. A novelty of the work is that the pressure due to a shock wave is not modeled as the product of a function of time and a function of space coordinates but its spatial and temporal dependence is found by solving the fluid-structure interaction problem. (C) 2019 Elsevier Ltd. All rights reserved.