Some measurements in the transitional supersonic wake of a transverse circular cylinder with emphasis on the effect of external noise
Abstract
The transition of the wake of a circular cylinder at M = 2.3 has been investigated in a low turbulence wind tunnel in which the stagnation pressure can be varied. The influence of the noise radiated by the nozzle walls boundary layers has been observed, and two possible mechanisms of interaction between the wake and the sound field are proposed. One is a fluttering motion on the viscous laminar wake due to a random motion of the stagnation and separation lines of the cylinder, the other is a direct interaction between the sound field and the verticity and entropy gradients in the laminar wake which has been shown to generate vorticity fluctuations. Methods, based on the interpretation of the hot wire anemometer signal, are proposed and justified to locate the statistical mean position of an initial, intermediate and final stage of transition, for a given Reynolds number.
- Publication:
-
In AGARD Laminar-Turbulent Transition 11 p (SEE N78-14316 05-34
- Pub Date:
- October 1977
- Bibcode:
- 1977ltt..agarQ....B
- Keywords:
-
- Boundary Layer Transition;
- Circular Cylinders;
- Sound Fields;
- Supersonic Wakes;
- Laminar Flow;
- Nozzle Walls;
- Viscous Flow;
- Vortices;
- Wall Flow;
- Wave Interaction;
- Fluid Mechanics and Heat Transfer