Laminar and turbulent nozzle-jet flows and their acoustic near-field

Bühler, Stefan; Obrist, Dominik; Kleiser, Leonhard (2014). Laminar and turbulent nozzle-jet flows and their acoustic near-field. Physics of Fluids, 26(8), 086103. AIP Publishing 10.1063/1.4890493

Full text not available from this repository. (Request a copy)

We investigate numerically the effects of nozzle-exit flow conditions on the jet-flow development and the near-field sound at a diameter-based Reynolds number of Re D = 18 100 and Mach number Ma = 0.9. Our computational setup features the inclusion of a cylindrical nozzle which allows to establish a physical nozzle-exit flow and therefore well-defined initial jet-flow conditions. Within the nozzle, the flow is modeled by a potential flow core and a laminar, transitional, or developing turbulent boundary layer. The goal is to document and to compare the effects of the different jet inflows on the jet flow development and the sound radiation. For laminar and transitional boundary layers, transition to turbulence in the jet shear layer is governed by the development of Kelvin-Helmholtz instabilities. With the turbulent nozzle boundary layer, the jet flow development is characterized by a rapid changeover to a turbulent free shear layer within about one nozzle diameter. Sound pressure levels are strongly enhanced for laminar and transitional exit conditions compared to the turbulent case. However, a frequency and frequency-wavenumber analysis of the near-field pressure indicates that the dominant sound radiation characteristics remain largely unaffected. By applying a recently developed scaling procedure, we obtain a close match of the scaled near-field sound spectra for all nozzle-exit turbulence levels and also a reasonable agreement with experimental far-field data.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Cardiovascular Engineering (CVE)

UniBE Contributor:

Obrist, Dominik

Subjects:

500 Science > 510 Mathematics
500 Science > 530 Physics
600 Technology > 620 Engineering

ISSN:

1070-6631

Publisher:

AIP Publishing

Language:

English

Submitter:

Dominik Obrist

Date Deposited:

12 Jun 2015 10:30

Last Modified:

26 Jun 2016 02:05

Publisher DOI:

10.1063/1.4890493

URI:

https://boris.unibe.ch/id/eprint/69381

Actions (login required)

Edit item Edit item
Provide Feedback