Observations of the flow from a rectangular nozzle
Abstract
An experimental investigation is described of the flow from two rectangular nozzles, for pressure ratio range up to 3, blowing into still air and into a stream flowing in the same direction as the jet, and having a Mach number of 0.74. The jet stream was observed by taking schlieren photographs, from which the positions of the shock waves were measured and related to those from a circular nozzle. Measurements were made of the jet pressure profiles at several stations along the length of the jet stream, and it is shown that the general shape of these profiles can be observed at a light screen using smoke injected into the air supply pipe for the jet. There was a substantial difference in the cross-sectional shape of the jet downstream of the nozzle for free stream Mach = 0 and 0.74 which was associated with vortices formed by the interaction between the external stream and the jet flow diverging from the sides of the nozzle exit. Additional evidence from a elliptical nozzle confirmed the conclusion that for a practical engine design with any flattened nozzle exit, vortices would be present in the flow with an external stream.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- 1975
- Bibcode:
- 1975STIN...7610417K
- Keywords:
-
- Free Jets;
- Nozzle Flow;
- Pressure Distribution;
- Schlieren Photography;
- Nozzle Geometry;
- Rectangles;
- Shock Waves;
- Smoke;
- Fluid Mechanics and Heat Transfer