Quantitative visualization of acoustically excited jets
Abstract
A technique is developed for quantitative characterization of three-dimensional vortex systems in jets from initially nonaxisymmetric nozzles. A pulsed laser is used to obtain phase-conditioned flow visualization images in a series of radial sections through the jet. Image processing techniques are developed for quantifying the vortex paths as a function of phase. By recombining the sectional images at fixed values of phase, an unwrapped representation of the shear layer is computed. In the case of an acoustically excited jet from an inclined nozzle, a partial-pairing mechanism is shown to be responsible for asymmetric shear-layer growth. Phase-conditioned, two-component laser Doppler velocity measurements are used to establish the validity of the imaging technique. The relative advantages of several processing schemes are also discussed.
- Publication:
-
26th AIAA Aerospace Sciences Meeting
- Pub Date:
- January 1988
- Bibcode:
- 1988aiaa.meetS....W
- Keywords:
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- Acoustic Excitation;
- Flow Visualization;
- Jet Flow;
- Image Processing;
- Laser Doppler Velocimeters;
- Quantitative Analysis;
- Three Dimensional Flow;
- Vortices;
- Acoustics