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Numerical Investigation of Second Mode Attenuation over Carbon/Carbon Surfaces on a Sharp Slender Cone

Sousa, Victor C. B. and Patel, Danish and Chapelier, J.-B. and Wagner, Alexander and Scalo, Carlo (2018) Numerical Investigation of Second Mode Attenuation over Carbon/Carbon Surfaces on a Sharp Slender Cone. AIAA Science and Technology Forum and Exposition (SciTech 2018), 08. -11. Jan. 2018, Kissimee, Florida USA.

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Official URL: http://scitech.aiaa.org/


Axisymmetric numerical simulations of a spatially developing hypersonic boundary layer over a sharp 7°-half-angle cone at M= 7.5, inspired by the experimental investigations by Wagner (2015), were carried out. Simulations are first performed with impermeable (or solid) walls with a one-time broadband pulse excitation applied upstream to determine the most convectively-amplified frequencies resulting in the range 260kHz - 400kHz, consistent with experimental observations of second-mode instability waves. Subsequently, we introduce harmonic disturbances via continuous periodic suction and blowing at 270 kHz and 350 kHz. For each of these forcing frequencies complex impedance boundary conditions (IBC), modeling the acoustic response of two different carbon/carbon (C/C) ultrasonically absorptive porous surfaces, are applied at the wall. The IBCs are derived as an output of a pore-scale aeroacoustic analysis - the inverse Helmholtz Solver (iHS) - which is able to return the broadband real and imaginary components of the surface-averaged impedance. The introduction of the IBCs in all cases leads to a significant attenuation of the harmonically-forced second-mode wave. In particular, we observe a higher attenuation rate of the introduced waves with frequency of 350 kHz in comparison with 270 kHz, and, along with the iHS impedance results, we establish that the C/C surfaces absorb acoustic energy more effectively at higher frequencies.

Item URL in elib:https://elib.dlr.de/119061/
Document Type:Conference or Workshop Item (Speech)
Title:Numerical Investigation of Second Mode Attenuation over Carbon/Carbon Surfaces on a Sharp Slender Cone
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Sousa, Victor C. B.vsousa (at) purdue.eduUNSPECIFIED
Patel, Danishpatel472 (at) purdue.eduUNSPECIFIED
Chapelier, J.-B.jchapeli (at) purdue.eduUNSPECIFIED
Wagner, AlexanderAlexander.Wagner (at) dlr.deUNSPECIFIED
Scalo, Carloscalo (at) purdue.eduUNSPECIFIED
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Keywords:hypersonic boundary-layer transition, ultrasonically absorptive coating, porous materials, acoustic absorption, UAT
Event Title:AIAA Science and Technology Forum and Exposition (SciTech 2018)
Event Location:Kissimee, Florida USA
Event Type:international Conference
Event Dates:08. -11. Jan. 2018
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Transport
DLR - Research area:Raumfahrt
DLR - Program:R RP - Raumtransport
DLR - Research theme (Project):R - Wiederverwendbare Raumfahrtsysteme und Antriebstechnologie
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Spacecraft, GO
Deposited By: Bachmann, Barbara
Deposited On:08 May 2018 14:37
Last Modified:08 May 2018 14:37

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