Characteristics of a horizontal square jet interacting with the free surface
- 23 June 2017
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Fluids
- Vol. 2 (6), 064607
- https://doi.org/10.1103/physrevfluids.2.064607
Abstract
The characteristics of a horizontal submerged square jet interacting with the free surface are investigated experimentally. A particle image velocimetry system is used to measure the mean flow and turbulent characteristics in the vertical symmetry plane of the jet at a Reynolds number of approximately 5500. It is shown that the effect of the free surface is to cancel the turbulent-nonturbulent interface and reduce the mean spanwise vorticity, Reynolds shear stress, and jet spreading rate in the upper shear layer in comparison to those measured in the lower shear layer. The results indicate that lowering of the jet offset height ratio increases the confinement effect of the free surface. Stronger confinement reduces the maximum mean streamwise velocity decay rate and mean surface velocity defect in the interaction region. The results also indicate a dramatic reduction in surface-normal turbulence intensity in the interaction region due to the damping effect of the free surface on the surface-normal velocity fluctuations. The decay of the surface-normal turbulence intensity near the free surface produces commensurate reductions in the surface-normal velocity fluctuation autocorrelation in the upper shear layer while enhancing the streamwise velocity fluctuation autocorrelation. The damping effect of the free surface on the surface-normal velocity fluctuations is found to be connected to the redistribution of the turbulent kinetic energy from the surface-normal velocity fluctuations to the streamwise velocity fluctuations.Funding Information
- Natural Sciences and Engineering Research Council of Canada
This publication has 31 references indexed in Scilit:
- The flow field in turbulent round free jetsProgress in Aerospace Sciences, 2012
- Near field dynamics of subsonic free square jets. A computational and experimental studyPhysics of Fluids, 1995
- Velocity measurements in a high-Reynolds-number, momentum-conserving, axisymmetric, turbulent jetJournal of Fluid Mechanics, 1994
- Noncircular jets in combustion systemsExperiments in Fluids, 1989
- TURBULENT NON-BUOYANT SURFACE JETSJournal of Hydraulic Research, 1984
- Coherent structures—reality and mythPhysics of Fluids, 1983
- Orderly structure in jet turbulenceJournal of Fluid Mechanics, 1971
- Some measurements in the self-preserving jetJournal of Fluid Mechanics, 1969
- The structure of a self-preserving turbulent plane jetJournal of Fluid Mechanics, 1965
- Experiments on the flow past a circular cylinder at very high Reynolds numberJournal of Fluid Mechanics, 1961