Numerical Simulation of Elastic Stress Wave Refraction at Air-Solid Interfaces

Elastic wave refraction at the air-solid interface and wave propagations in the vicinity of the air-solid interface are numerically studied. The modified ghost fluid method (MGFM) and isobaric fix methods are combined to solve the fluid and solid statuses at the air-solid interface and construct a continuous boundary condition for the air-solid interface. The states in the ghost domain are evaluated by the MGFM-algorithm. The solid governing equations are solved with second order spatial discretization. Numerical tests verify the correctness of the presented continuous boundary condition and show that the combined method is convergent in the vicinity of the air-solid interface. The 3D numerical results by the combined method are close to those of the Arbitrary-Lagrangian-Eulerian (ALE) method. The combined method is robust when applied for multi-dimensional problems. A compression stress wave impacting on the air-solid interface result in a compression wave in air. A tension stress wave impacting on the air-solid interface result in an expansion wave in air.