Wagner, Alexander and Hannemann, Klaus and Kuhn, Markus (2014) Ultrasonic absorption characteristics of porous carbon–carbon ceramics with random microstructure for passive hypersonic boundary layer transition control. Experiments in Fluids, 55 (6), pp. 1-9. Springer Nature. doi: 10.1007/s00348-014-1750-4. ISSN 0723-4864.
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Official URL: http://link.springer.com/article/10.1007%2Fs00348-014-1750-4
Abstract
Preceding studies in the high enthalpy shock tunnel Göttingen of the German Aerospace Center (DLR) revealed that carbon fibre reinforced carbon ceramic (C/C) surfaces can be utilized to damp hypersonic boundary layer instabilities leading to a delay of boundary layer transition onset. To assess the ultrasonic absorption properties of the material, a test rig was set up to measure the reflection coefficient at ambient pressures ranging from 0.1 9 10^5 to 1 9 10^5 Pa. For the first time, broadband ultrasonic sound transducers with resonance frequencies of up to 370 kHz were applied to directly cover the frequency range of interest with respect to the second-mode instabilities observed in previous experiments. The reflection of ultrasonic waves from three flat plate test samples with a porous layer thickness between 5 and 30 mm was investigated and compared to an ideally reflecting surface. C/C was found to absorb up to 19 % of the acoustic power transmitted towards the material. The absorption characteristics were investigated theoretically by means of the quasi-homogeneous absorber theory. The experimental results were found to be in good agreement with the theory.
Item URL in elib: | https://elib.dlr.de/89370/ | ||||||||||||||||
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Document Type: | Article | ||||||||||||||||
Additional Information: | Published online: 27 May 2014 | ||||||||||||||||
Title: | Ultrasonic absorption characteristics of porous carbon–carbon ceramics with random microstructure for passive hypersonic boundary layer transition control | ||||||||||||||||
Authors: |
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Date: | 2014 | ||||||||||||||||
Journal or Publication Title: | Experiments in Fluids | ||||||||||||||||
Refereed publication: | Yes | ||||||||||||||||
Open Access: | No | ||||||||||||||||
Gold Open Access: | No | ||||||||||||||||
In SCOPUS: | Yes | ||||||||||||||||
In ISI Web of Science: | Yes | ||||||||||||||||
Volume: | 55 | ||||||||||||||||
DOI: | 10.1007/s00348-014-1750-4 | ||||||||||||||||
Page Range: | pp. 1-9 | ||||||||||||||||
Publisher: | Springer Nature | ||||||||||||||||
ISSN: | 0723-4864 | ||||||||||||||||
Status: | Published | ||||||||||||||||
Keywords: | porous carbon–carbon ceramics, hypersonic boundary layer transition, ultrasonic waves, ultrasonically absorptive coatings (UAC) | ||||||||||||||||
HGF - Research field: | Aeronautics, Space and Transport | ||||||||||||||||
HGF - Program: | Space | ||||||||||||||||
HGF - Program Themes: | Space Transportation | ||||||||||||||||
DLR - Research area: | Raumfahrt | ||||||||||||||||
DLR - Program: | R RP - Space Transportation | ||||||||||||||||
DLR - Research theme (Project): | R - Raumfahrzeugsysteme - Numerische Verfahren und Simulation (old) | ||||||||||||||||
Location: | Göttingen , Stuttgart | ||||||||||||||||
Institutes and Institutions: | Institute of Aerodynamics and Flow Technology > Spacecraft Institute of Structures and Design > Space System Integration | ||||||||||||||||
Deposited By: | Micknaus, Ilka | ||||||||||||||||
Deposited On: | 14 Jul 2014 15:38 | ||||||||||||||||
Last Modified: | 06 Nov 2023 14:46 |
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