Turbulent pulsations in the axisymmetrical submerged jet

Abstract

Today, the turbulent characteristics of laminar jets remain almost unexplored, although all real flows have a pulsating component, which in technological processes can have a significant effect on the processes of mixing, heat and mass transfer. The turbulent characteristics of a submerged laminar air jet flowing out of a tube with a diameter of 3.2 mm and length of more than 100 diameters were experimentally investigated at Reynolds number of 436. The measurements were carried out using a hot-wire anemometer. The ranges of operating parameters at which the laminar, transitional and turbulent flows occur in the jet source have been determined. Based on the data obtained, the regime for the study was selected. For the selected regime, the profiles of average velocities and pulsations in cross-sections along the jet flow were measured and distributions of turbulent characteristics along the jet flow on the axis and in the mixing layers were constructed.