Measurements of a separating turbulent boundary layer
Abstract
The directionally sensitive laser anemometer now provides the ability to accurately measure instantaneous flow direction and magnitude. The experimental results are concerned with a nominally two dimensional separating turbulent boundary layer for an airfoil type flow in which the flow was accelerated and then decelerated until separation. Upstream of separation single and cross wire hot wire anemometer measurements are also presented. Measurements obtained in the separated zone with a directionally sensitive laser anemometer system are presented. Results lead to significant conclusions about the nature of the separated flow when the thickness of the backflow region is small as compared with the shear laer thickness. The backflow is controlled by the large scale outer region flow. The small mean backflow does not come from far downstream, but appears to be supplied intermittently by large scale structures as they pass through the separated flow. Downstream of fully developed separation, the mean backflow appears to be divided into three layers.
- Publication:
-
Technical Report
- Pub Date:
- April 1980
- Bibcode:
- 1980puwl.reptR....S
- Keywords:
-
- Boundary Layer Flow;
- Laser Doppler Velocimeters;
- Separated Flow;
- Shear Stress;
- Turbulent Boundary Layer;
- Airfoils;
- Anemometers;
- Fluid Flow;
- Shear Layers;
- Turbulent Flow;
- Fluid Mechanics and Heat Transfer