Separated flow around cylinders
Abstract
Unsteady properties of the near wakes of cylinders were studied for large Reynolds numbers and at transonic speeds. Tests were carried out on four cylinders in a transonic wind tunnel. Two cylinders were investigated with flows having Reynolds number between 336,000 and 483,000. Two other cylinders were observed in transonic flows with Mach number varying from 0.70 to 0.98 and Reynolds number between 100,000 and 180,000. Experiments consisted in visualizing the flow by ultrahigh speed spark shadowgraph photography. Results show that the vortex street subsists up to the highest Reynolds number tested and that the Strouhal number remains constant near 0.2. A coupling between the vortex street and the flow is maximal at critical Mach. It disappears as soon as shock waves prevent perturbations induced by unsteady motions of the vortex street from going upstream.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- February 1980
- Bibcode:
- 1980STIN...8222472D
- Keywords:
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- Cylindrical Bodies;
- Flow Visualization;
- Near Wakes;
- Separated Flow;
- Vortex Streets;
- Wind Tunnel Tests;
- Mach Number;
- Reynolds Number;
- Shadowgraph Photography;
- Transonic Flow;
- Unsteady Flow;
- Fluid Mechanics and Heat Transfer