Studies on Fluid Jets Discharging Normally into Moving Liquids

Abstract

Results of tests on circular water and air-water mixture jets impinging normally into a water tunnel flow are given. Data taken on jet penetration are in agreement with results of previous experiments by others conducted in wind tunnels at jet-tunnel velocity ratios of six and less. A secondary effect is present at higher velocity ratios so that the penetration is deeper than previously indicated. An empirical penetration parameter developed by the National Advisory Committee for Aeronautics [11] may be used for correlation of air-water mixture penetration data if the orifice is considered reduced in size by an amount equal to the area occupied by the air bubbles. Entrainment of external flow is shown photographically. The studies indicate that entrainment from the wake of the jet proceeds in a periodic manner. Total pressure data are in qualitative agreement with previous experiments conducted in wind tunnels. These show the characteristic kidney-shaped deformation predicted theoretically by Lu [3] and by Fraser [5] . An analysis of the two-dimensional or slot jet is presented for the case where the two flows are under the same total pressure. Comparison with penetration data on three-dimensional jets indicates that the rapid flattening of the jet gives it a quasi two-dimensional character.