Rossignol, Karl-Stéphane and Delfs, Jan Werner and Boden, Fritz (2015) On the Relevance of Convection Effects for a Laser-Generated Sound Source. In: 21st AIAA/CEAS Aeroacoustics Conference, 2015. 21st AIAA/CEAS Aeroacoustics Conference, Dallas, USA. doi: 10.2514/6.2015-3146.
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Abstract
A laser-generated sound source is used to generate a nearly omni-directional sound field. This sound field is investigated experimentally to reveal its characteristics as a function of the surrounding medium mean velocity. It is found that the sound source approximately has monopole character when generated in a stagnant medium. Increas- ing the surrounding flow velocity leads to a positive Doppler-shift combined with a convective amplification for an observer downstream of the source while the reverse is observed upstream of the source. The laser sound source behaves therefore as a convected point heat source in a uniform flow. A solution of the convected wave equa- tion for a moving point heat source in a uniform subsonic flow is derived, providing a closed-form description of the source and appropriate scaling parameters for exper- imental results. The derived theoretical model enables the determination of the heat release function resulting from the laser energy deposition in the medium and associ- ated to the measured far-field pressure pulses. An implementation of the heat release function in CAA codes is straigthforward, making numerical replication of shielding tests with the laser sound source possible.
Item URL in elib: | https://elib.dlr.de/100145/ | ||||||||||||||||
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Document Type: | Conference or Workshop Item (Speech) | ||||||||||||||||
Title: | On the Relevance of Convection Effects for a Laser-Generated Sound Source | ||||||||||||||||
Authors: |
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Date: | 2015 | ||||||||||||||||
Journal or Publication Title: | 21st AIAA/CEAS Aeroacoustics Conference, 2015 | ||||||||||||||||
Refereed publication: | Yes | ||||||||||||||||
Open Access: | No | ||||||||||||||||
Gold Open Access: | No | ||||||||||||||||
In SCOPUS: | Yes | ||||||||||||||||
In ISI Web of Science: | No | ||||||||||||||||
DOI: | 10.2514/6.2015-3146 | ||||||||||||||||
Status: | Published | ||||||||||||||||
Keywords: | Aeroacoustic, Sound source, Laser, Noise Shielding, Wind tunnel testing | ||||||||||||||||
Event Title: | 21st AIAA/CEAS Aeroacoustics Conference | ||||||||||||||||
Event Location: | Dallas, USA | ||||||||||||||||
Event Type: | international Conference | ||||||||||||||||
HGF - Research field: | Aeronautics, Space and Transport | ||||||||||||||||
HGF - Program: | Aeronautics | ||||||||||||||||
HGF - Program Themes: | fixed-wing aircraft | ||||||||||||||||
DLR - Research area: | Aeronautics | ||||||||||||||||
DLR - Program: | L AR - Aircraft Research | ||||||||||||||||
DLR - Research theme (Project): | L - Flight Physics (old) | ||||||||||||||||
Location: | Braunschweig , Göttingen | ||||||||||||||||
Institutes and Institutions: | Institute of Aerodynamics and Flow Technology > Technical Acoustics Institute of Aerodynamics and Flow Technology > Experimental Methods | ||||||||||||||||
Deposited By: | Rossignol, Karl-Stephane | ||||||||||||||||
Deposited On: | 09 Dec 2015 13:46 | ||||||||||||||||
Last Modified: | 19 Jul 2023 14:01 |
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