Compressible spreading rates of supersonic coaxial jets
Abstract
The compressible spreading rates of two supersonic coaxial jets were studied experimentally. The center jet had a fully-expanded Mach number of 3, and the outer jet of M = 1.8. The geometries of the center jet were circular and rectangular with two configurations, both with a 3∶1 aspect-ratio. The convective Mach numbers were varied in the range between 0.25 < M c< 2.25. This was accomplished by varying the density ratio between the center jet and the coaxial jet, as well as the velocity ratio. The experimental compressible spreading rate was determined using Schlieren photography and total-pressure measurements. The spreading rate of the center circular jet decreased with increasing convective Mach number until it reached a constant value of 0.2 to 0.3 of the incompressible spreading rate for M c>1.4. The rectangular jets exhibited a similar drop, at the same range of M c, but their spreading rate was higher relative to the circular jet in the entire convective Mach number range.
- Publication:
-
Experiments in Fluids
- Pub Date:
- December 1990
- DOI:
- 10.1007/BF00215025
- Bibcode:
- 1990ExFl...10..161S
- Keywords:
-
- Annular Flow;
- Coaxial Flow;
- Compressible Flow;
- Flow Distribution;
- Jet Mixing Flow;
- Supersonic Jet Flow;
- Air Breathing Engines;
- Aspect Ratio;
- Flow Geometry;
- Free Jets;
- Mach Number;
- Schlieren Photography;
- Fluid Mechanics and Heat Transfer