A numerical study on high-speed water jet impact

Abstract The usage of water jets has spread into numerous fields and for multifaceted purposes such as cleaning, cutting, and punching various materials. Because the impact occurs over an extremely short period, the target may deform elastically or plastically at high rates of strain. The dynamics of this process are complex and not fully understood. This paper applies a numerical method to simulate the phenomenon. A water jet with a spherical head was used at a speed of 570 m/s to impact on a structure, which was a flat plate made of Polymethyl-Methacrylate (PMMA). The Couple Eulerian Lagragian (CEL) method was used to simulate the entire process and eliminated abruption caused by large distortion of elements. Water-hammer pressure and the subsequent stagnation pressure on the surface of the plate were performed to evaluate the distribution of the pressure on the impact surface and the resulting deformation of the structure. The simulation results were reflected in the calculation using empirical formulas and were further validated using Obara's experiment. Whereas facets of this phenomenon could not be fully modeled, the numerical simulation supplied accurate quantitative details of stress, strain, and deformation fields that would be costly and difficult to reproduce experimentally.