Development of a two-stream mixing layer from tripped and untripped boundary layers
Abstract
The effects of the state of the initial boundary layers on the development of a two-stream, plane mixing layer, with a velocity ratio of 0.6 are experimentally investigated. Spanwise-average profiles are compared for the first time. The results indicate that both the near and far-field growth rates for the untripped case are significantly higher than the tripped case. The maximum Reynolds stresses and higher-order products for the two cases behave very differently in the near-field, but asymptote to approximately the same constant levels far downstream. The mean velocity and turbulence profiles in this region also collapse adequately for the two cases when plotted in similarity coordinates. The distance required to achieve self-similarity is distinctly shorter for the tripped case, in contrast to previous observations. The higher growth rate for the untripped case is attributed to the presence of streamwise vortices which result in additional entrainment by the mixing layer.
- Publication:
-
AIAA, Aerospace Sciences Meeting
- Pub Date:
- January 1990
- Bibcode:
- 1990aiaa.meetQQ...B
- Keywords:
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- Boundary Layer Flow;
- Mixing Layers (Fluids);
- Mixing Length Flow Theory;
- Turbulent Mixing;
- Wind Tunnel Tests;
- Laminar Flow;
- Turbulent Flow;
- Two Dimensional Boundary Layer;
- Two Fluid Models;
- Fluid Mechanics and Heat Transfer