An experimental investigation of a round turbulent jet in a cross-flow
Abstract
The behavior of a round turbulent jet in a cross flow is of considerable importance to the operation of very short takeoff and landing (VSTOL) aircraft. An experimental investigation of the turbulent jet flow that results when a circular jet is injected perpendicularly from an elevated source into a uniform, steady cross source is described. Mean and root mean square velocity isocontours of the vertical center plane depicted the spread of the isothermal jet and its interaction with the cross flow and the wake behind the stack. Interactions below the center line of the jet involving the jet wake and the stack wake was wide and diffuse in comparison with the interaction region above the jet center line. Mean velocity isocontours provided the characteristics of the overall spread of a jet in a cross wind. Mean temperature isocontours for a heated jet in a cross wind provided a clear picture of the average shape of the jet since temperature acts as a tracer. A comparison of the isothermal contour plots obtained at various downstream locations establishes that the cross sectional shape of the jet evolves from a kidney shape in the near field to a roughly round shape in the far field. Autospectra of the temperature signals reveal that, in the lower region, a distinct frequency centered activity exists, there being a marked peak in the auto spectrum at a frequency of about 50 Hz. By contrast, no such activity exists in the upper region.
- Publication:
-
13th Canadian Congress of Applied Mechanics
- Pub Date:
- May 1991
- Bibcode:
- 1991ccam.proc..492H
- Keywords:
-
- Cross Flow;
- Flow Distribution;
- Jet Flow;
- Temperature Distribution;
- Turbulent Flow;
- Flow Geometry;
- Flow Velocity;
- Flow Visualization;
- Vertical Takeoff Aircraft;
- Wakes;
- Fluid Mechanics and Heat Transfer