Controlled excitation of a cold turbulent swirling free jet
Abstract
Experimental results from acoustic excitation of a cold free turbulent jet with and without swirl are presented. A flow with a swirl number of 0.35 (i.e., moderate swirl) is excited internally by plane acoustic waves at a constant sound pressure level and at various frequencies. It is observed that the cold swirling jet is excitable by plane waves, and that the instability waves grow about 50 percent less in peak rms amplitude, and saturate further upstream compared to corresponding waves in a jet without swirl having the same axial mass flux. The preferred Strouhal number based on the mass-averaged axial velocity and nozzle exit diameter for both swirling and nonswirling flows is 0.4. So far no change in the mean velocity components of the swirling jet is observed as a result of excitation.
- Publication:
-
ASME Journal of Vibration Acoustics
- Pub Date:
- April 1988
- Bibcode:
- 1988ATJVA.110..234T
- Keywords:
-
- Acoustic Excitation;
- Flow Stability;
- Free Jets;
- Swirling;
- Turbulent Jets;
- Plane Waves;
- Sound Pressure;
- Strouhal Number;
- Turbulent Flow;
- Fluid Mechanics and Heat Transfer