Characteristics of swirling flow exhausting from nozzles with curved walls
Abstract
This paper describes some LDA measurements made in a highly swirling flow exhausting from a nozzle with strongly curved walls. In comparison with the flow produced by a parallel-sided exahust nozzle the recirculation zone is expanded very considerably in diameter, due to the fact that the swirling flow sticks to the strong curvature, and is discharged from the nozzle in a near radial jet. Up to 6 times the initial mass flow rate is recirculated, compared to 0.35 times when using the parallel-sided nozzle. The precessing vortex core (P.V.C.) also follows the strong curvature of the exhaust nozzle, and considerable reduction in Strouhal number occurs. This gives rise to regions of reversed mean tangential velocity in the center of the recirculation zone, apparently connected with the presence of coherent vortical structures.
- Publication:
-
Applications of Laser-Doppler Anemometry to Fluid Mechanics
- Pub Date:
- 1982
- Bibcode:
- 1982alaf.symp...10S
- Keywords:
-
- Exhaust Nozzles;
- Flow Characteristics;
- Flow Measurement;
- Laser Doppler Velocimeters;
- Nozzle Geometry;
- Swirling;
- Wall Flow;
- Laser Anemometers;
- Mass Flow Rate;
- Recirculative Fluid Flow;
- Strouhal Number;
- Test Equipment;
- Fluid Mechanics and Heat Transfer