Effect of 3D submerged jet shape on maximum pressure of plunge pool bottom

Abstract

Maximum pressure is one of the key factors that affect jet scouring. Previous studies have focused on the attenuation characteristics of the submerged jet, but there are few studies on the influence of the nappe shape on the pressure of the plunge pool. In this paper, a combination of numerical simulation and physical experiments was used to determine the influence on the maximum pressure of the vertical rectangular submerged jet with different aspect ratios (1, 3, 5, 8, 11.25, 15, and 20), incident flow velocity, and water depth on the plunge pool bottom. The hydraulic diameter, D, of the entering interface was proposed to measure the degree of dispersion of the nappe, based on which an empirical formula for the maximum pressure on the plunge pool bottom was obtained. By applying the formula to other shapes of jets (rhombuses, triangles, circles, ellipses, etc.), higher precision calculation results were also obtained, and the formula calculation results were in good agreement with the test results of the existing literature.