Cooperative Investigation of the Noise Producing Region of an Axisymmetric Jet.
STATE UNIV OF NEW YORK AT BUFFALO FACULTY OF ENGINEERING AND APPLIED SCIENCES
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The objectives of this three-university effort are to determine whether or not large scale structures exist in the mixing layer of an axisymmetric jet to determine whether or not these large scale structures if they exist contribute to the radiated noise and to quantify the above conclusions so that the results can be used for evaluation of jet noise theories and for prediction of radiated noise. This is a report on the initial phase of the work in which the primary emphasis has been on the construction of the experimental facilities, the acquisition and assembly of the measurement hardware and the development of computer software. Noteworthy advances include an analysis and extension of the burst-mode LDA, and the continued development of digitally sampled flow visualization techniques. Experiments on various nozzle shapes at low Reynolds number indicate that nozzle shape plays an important role in determining the vortex pairing in the mixing layer and the radiated noise. This does not appear to be the case at high Reynolds numbers. The preliminary conclusion is that the pairing and turbulence structures observed at low Reynolds numbers have little to do with jet noise. Author
- Fluid Mechanics