Interaction of a turbulent round jet with the free surface
Abstract
An experimental study of the interaction of an underwater turbulent round jet with the free surface was conducted. Flow visualization, surface curvature measurements, and hot film velocity measurement 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 approach the free surface. These waves propagate at angle with respect to the flow direction. The propagation angle increases as the strength of the interaction is increased by increasing the momentum flux of the jet or reducing the distance of the jet to the free surface or both. Propagation of these waves in the flow direction is suppressed by the surface current produced by the jet. The fundamental scaling parameters of the free-surface jet is determined. The velocity scale is the velocity obtained from the combination of jet momentum, density and depth of the jet and the scale is the distance of the jet to the free surface. It is shown that the centerline velocity decay when scaled with these parameters collapses to a universe curve for different depths of the jet. The asymptotic decay in the far field is reduced by a factor of 2(sup 1/2) compared to the free jet due to the confinement by the free surface. The growth rate of the free-surface jet is found in good agreement with the free jet. However the eccentricity of the jet cross section caused by the displacement of the jet centerline persists for large distances downstream, beyond 40 times the initial depth of the jet centerline. Measurements are also reported on the flow field of a jet moving parallel to a solid surface. These results are compared with the results for the free surface jet.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1989
- Bibcode:
- 1989PhDT........39M
- Keywords:
-
- Flow Distribution;
- Flow Visualization;
- Free Jets;
- Jet Flow;
- Surface Waves;
- Turbulent Jets;
- Confinement;
- Displacement;
- Eccentricity;
- Far Fields;
- Momentum;
- Solid Surfaces;
- Velocity Measurement;
- Fluid Mechanics and Heat Transfer