Interaction of a turbulent round jet with the free surface

Abstract

The interaction of a turbulent round jet with the free surface was investigated experimentally. Flow visualization, free-surface curvature measurements and hot-film velocity measurements were used to study this flow. It is shown that surface waves are generated by the large-scale vortical structures in the jet flow as they interact with the free surface. These waves propagate at an angle with respect to the flow direction which increases as the Froude number is increased. Propagation of the waves in the flow direction is suppressed by the surface current produced by the jet. Farther downstream the surface motions are caused by the large-scale vortical structures. Characteristic dark circular features are observed in shadowgraph images associated with concentrated vorticity normal to the free surface. The normal vorticity is believed to be the result of vortex line reconnection processes in the turbulent flow. Measurements of the mean velocity and turbulence intensity are reported. Owing to the confinement by the free surface, the decay rate of the maximum mean velocity is reduced by a factor of √2 compared to an unconfined jet.

Analysis of Turbulent Mixing Jets in a Large Scale Tank

“…That behavior does not have a significant impact on the flow patterns inside the slurry region in a deep tank [19]. The fluid properties of water were evaluated at room temperature (20 o C).…”

Sludge Heel Removal Analysis for Slurry Pumps of Tank 11

“…This information will assist in the sludge suspension and removal plans for Tank 11 operations. The steady-state flow patterns on the horizontal discharge plane follow a series of parabolic curves similar to that of a free jet [10,11]. Vertical velocity profiles are changed from a bell-shaped curve near the exit of the nozzle to a near-uniform velocity near the tank wall boundary.…”

“…3 [6,10,11]. Most mixing action and entrainment takes place in the region of fully-developed flow which begins at a distance of approximately eight nozzle diameters from the discharge plane.…”

Flow visualization and free surface length scales measurements in a horizontal jet beneath a free surface

“….). In the literature, few works appear on flow visualizations [6,7]. This paper also attempts to fill a part of this lack.…”

“…Following these experimental processes, results were dedicated to the description of the mean and turbulent velocity fields as well as the void fraction, bubble size and frequency [13]. Except the contributions of Walker et al [6] or Madnia and Bernal [7], the literature related to flow visualization aiming to estimate characteristic length scales of the free surface and comparison with measurements is sparse although this kind of information could be helpful for scientists, biologists or coastal engineers. This paper also presents flow visualizations and free surface length scale measurements made in the context of a horizontal jet closed to an air/water interface.…”