Unsteady separated flow behind a normal plate calculated by discrete-vortex model. I - Velocity-point scheme. II - Modification of velocity-point scheme
Abstract
A discrete-vortex model has been developed to predict the characteristics of the separated flow past a normal plate immersed in a uniform approaching stream. Provided that the distance between the velocity points and the edges of the plate is appropriately selected, the Strouhal number agrees extremely well with experiment, while the time-averaged values of the drag coefficient and rate of shedding of vorticity from the separation points are approximately 9% smaller and 20-40% larger than experimental results, respectively. The discrete-vortex model suffers from an insufficient cancellation of vorticity in the formation region, however, and an artificial reduction in the strength of vortices, as a function of their age, is incorporated into the scheme. This gives the root-mean-square values of the fluctuating velocity components an accuracy comparable to that obtained by means of sophisticated turbulence-model equations (Pope and Whitelaw, 1976), but the calculated value of the Strouhal number is 33% larger than shown by experiment.
- Publication:
-
Hokkaido University Faculty Engineering Memoirs
- Pub Date:
- December 1979
- Bibcode:
- 1979HUFEM..15..199K
- Keywords:
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- Bluff Bodies;
- Flow Characteristics;
- Separated Flow;
- Submerged Bodies;
- Unsteady Flow;
- Vorticity;
- Flow Distortion;
- Flow Velocity;
- Plates (Structural Members);
- Strouhal Number;
- Turbulence Models;
- Fluid Mechanics and Heat Transfer