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Experimental investigation of the effect of transpiration cooling on second mode instabilities in a hypersonic boundary layer

Ponchio Camillo, Giannino and Wagner, Alexander and Dittert, Christian and Benjamin, Leroy and Wartemann, Viola and Neumann, Jens and Hink, Rüdiger (2020) Experimental investigation of the effect of transpiration cooling on second mode instabilities in a hypersonic boundary layer. Experiments in Fluids, 61 (162), pp. 1-19. Springer Nature. doi: 10.1007/s00348-020-02994-8. ISSN 0723-4864.

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Official URL: https://link.springer.com/article/10.1007/s00348-020-02994-8


The influence of localized nitrogen transpiration on second mode instabilities in a hypersonic boundary layer is experimentally investigated. The study is conducted using a 7deg half-angle cone with a length of 1100 mm and small nose bluntness at 0deg angle of attack. Transpiration is realized through a porous Carbon/Carbon patch of 44×82 mm located near the expected boundary layer transition onset location. Transpiration mass flow rates in the range of 0.05–1% of the equivalent boundary layer edge mass flow rate were used. Experiments were conducted in the High Enthalpy Shock Tunnel Göttingen (HEG) at total enthalpies around 3 MJ/kg and unit Reynolds numbers in the range of 1.4e6 to 6.4e6 1/m. Measurements were conducted by means of coaxial thermocouples, Atomic Layer Thermopiles (ALTP), pressure transducers and high-speed schlieren. The present study shows that the most amplified second mode frequencies were shifted to lower values as nitrogen is transpired into the boundary layer. In some cases the instability amplitudes were found to be significantly reduced. The observed frequency reduction was verified to correlate with the change of the relative sonic line height in the boundary layer. The amplitude damping was observed to occur only until the most amplified frequencies were reduced to around 50% of their undisturbed values. When transpiration within this limit was performed shortly upstream of the natural boundary layer transition onset, a transition delay of approximately 17% could be observed.

Item URL in elib:https://elib.dlr.de/135429/
Document Type:Article
Title:Experimental investigation of the effect of transpiration cooling on second mode instabilities in a hypersonic boundary layer
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Ponchio Camillo, GianninoUNSPECIFIEDhttps://orcid.org/0000-0002-2178-0777UNSPECIFIED
Wagner, AlexanderUNSPECIFIEDhttps://orcid.org/0000-0002-9700-1522UNSPECIFIED
Dittert, ChristianUNSPECIFIEDhttps://orcid.org/0000-0001-7839-3359UNSPECIFIED
Benjamin, LeroyUNSPECIFIEDhttps://orcid.org/0000-0003-3034-1917UNSPECIFIED
Wartemann, ViolaUNSPECIFIEDhttps://orcid.org/0000-0002-1920-3364UNSPECIFIED
Date:27 June 2020
Journal or Publication Title:Experiments in Fluids
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 1-19
EditorsEmailEditor's ORCID iDORCID Put Code
Publisher:Springer Nature
Keywords:hypersonic boundary layer, second mode instability, hypersonic transition, transpiration cooling, HEG, transition delay, porous surface, gas injection
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 - Wiederverwendbare Raumfahrtsysteme (old)
Location: Braunschweig , Göttingen , Stuttgart
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Spacecraft, GO
Institute for Aerodynamics and Flow Technology > Spacecraft, BS
Institute of Structures and Design > Space System Integration
Institute of Aeroelasticity > Aeroelastic Simulation
Deposited By: Wagner, Alexander
Deposited On:03 Jul 2020 10:06
Last Modified:23 Oct 2023 12:36

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