Direct evaluation of aeroacoustic theory in a jet
Abstract
Aeroacoustic theory is applied to low-Mach (M = 0.08) cold jets, focusing on motion at scales which allow the assumption that the entire jet diameter is acoustically compact. The primary result is that the measured sound field directivity of vortex ring pairing in circular jets is similar to that predicted by the theory: a stationary axisymmetric lateral quadrupole. It is also shown that pairing of purely axisymmetric coherent structures is not the dominant sound source in low-Mach-number jets and that vortex asymmetry must be an essential aspect of the vortex motions which produce noise in such jets.
- Publication:
-
Journal of Fluid Mechanics
- Pub Date:
- July 1992
- DOI:
- 10.1017/S0022112092000168
- Bibcode:
- 1992JFM...240..469B
- Keywords:
-
- Aeroacoustics;
- Aerodynamic Noise;
- Jet Flow;
- Mach Number;
- Sound Fields;
- Vortex Rings;
- Inviscid Flow;
- Nozzle Design;
- Sound Pressure;
- Test Facilities;
- Vorticity;
- Acoustics