Flow structures in the developing region of a symmetric wake and an unsymmetric wake
Abstract
A conditional sampling technique was designed and employed to determine the ensemble-averaged flow structures in the developing region of a symmetric wake (r=1.0) and an unsymmetric wake (r=0.5). It was found that at a velocity ratio of 0.5 the large scale structure, which was observed from a reference frame traveling with its phase speed, is initially confined in the high-speed stream, elongated in the stream direction, and is shaped elliptically. As the flow convects downstream it grows in the cross-stream direction, as well as tilting toward the wake center, and then evolves into a nearly circular shape. Results for a velocity ratio of 1.0, corresponding to the case of a 2-D wake flow, show that two rows of counter-rotating vortices develop in two streams originating in the linear instability region. Similar to the case for r=0.5, these vortices grow, as well as tilt, when the flow convects them downstream. However, the growth rate of these flow structures is slower than that of the case for r=0.5.
- Publication:
-
Physics of Fluids
- Pub Date:
- August 1987
- DOI:
- 10.1063/1.866129
- Bibcode:
- 1987PhFl...30.2389M
- Keywords:
-
- Axisymmetric Flow;
- Flow Geometry;
- Flow Velocity;
- Wakes;
- Wind Tunnel Tests;
- Flow Characteristics;
- Flow Measurement;
- Low Speed Wind Tunnels;
- Spatial Distribution;
- Two Dimensional Flow;
- Vortices;
- Fluid Mechanics and Heat Transfer