Experimental and computational study of tones occurring with a coaxial nozzle
| Autor: | Amy F. Fagan, Ivana Milanovic, Christopher J. Miller, Khairul Q. Zaman |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
020301 aerospace & aeronautics
Materials science Acoustics and Ultrasonics Coaxial nozzle Acoustics Nozzle Aerospace Engineering 02 engineering and technology Propulsion 01 natural sciences 010305 fluids & plasmas Mechanism (engineering) Tone (musical instrument) 0203 mechanical engineering 0103 physical sciences |
| Zdroj: | International Journal of Aeroacoustics. 18:189-206 |
| ISSN: | 2048-4003 1475-472X |
| DOI: | 10.1177/1475472x19834522 |
| Popis: | The source of audible tones occurring with a coaxial nozzle is explored experimentally as well as computationally. The hardware is comprised of an inner and an outer nozzle, without a center-body, that are held together by a set of four struts. With increasing jet Mach number ( Mj), first a tone occurred at about 2550 Hz around Mj = 0.06. At higher Mj, a tone at 5200 Hz dominated the noise spectra. The corresponding non-dimensional frequency, based on the effective thickness of the inner nozzle lip and jet exit velocity, turned out to be about 0.2, a value characteristic of Karman vortex shedding. Thus, vortex shedding from the inner nozzle lip could be linked to the tones. From a comparison of acoustic wavelengths and nozzle dimensions, as well as locations of the pressure nodes and anti-nodes from the computational results, it was inferred that the vortex shedding excited one-quarter-wave resonances within the divergent sections of the nozzle. Such resonances in the inner and the outer nozzles produced the higher and the lower frequency tones, respectively. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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