Self-oscillation regimes of the penetration of free conical thin-walled turbulent jets through a fluid surface

Abstract

Certain results of an experimental investigation of hydrodynamic effects occurring, when free thin-walled turbulent jets issuing from a conical slot nozzle with a vertical axis penetrate through the surface of a fluid in a rectangular reservoir, are presented. The ranges of the jet flow rate and the spacing between the nozzle and the free surface, on which stable regular transverse self-oscillations of the boundaries of dome-shaped jets are observable, are determined. For fixed values of the conicity angle α = 60° and the nozzle slot width δ = 0.1 cm the characteristic form of the dependence of the self-oscillation period on the jet flow rate and the spacing between the slot nozzle and the free surface (dome height) is presented. The self-oscillation regime generation mechanism, together with the possible reasons for the revealed bifurcation changeover of the oscillation mode at certain values of the governing parameters and the hysteresis effects, are discussed. The salient features of the flows occurring on the surface and within the fluid beneath the dome are described.