A numerical study on the transient impulsive pressure of a water jet impacting nonplanar solid surfaces

Abstract

This paper presents an in-depth investigation into the transient impulsive pressure of an arc-curved water jet impacting a solid surface. The emphasis of this study is on the variations of the surface shape, which are classified into four types: The flat surface, the concave surface, the convex surface and the inclined surface. The numerical tool of arbitrary Lagrangian-Eulerian formulations is used to model the arc-curved jet impacting these different solid surface types. Elaborately designed experiments were conducted to test the impulsive pressure profile; the experimental results are found to be in approximate agreement with the numerical results. The impulsive pressure profiles of water jet impacting the flat and inclined solid surface are observed to exhibit two quintessential stages, in line with the traditional pressure profile; however, a double/multiple-peaked pressure structure is observed for the cases of the water jet impacting the concave and convex solid surfaces. Additionally, the value of the peak pressure is found to be a quadratic representation with the jet velocity, and the duration of the peak pressure is found to be an exponential representation with the jet velocity. The compression degrees of the liquid jet impacting the different surfaces are validated to be the root cause for the discrepancy of the impulsive pressure.