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Pressure gradient effects on wake flow instabilities behind isolated roughness elements on re-entry capsules

Theiß, Alexander and Leyh, Sascha and Hein, Stefan (2017) Pressure gradient effects on wake flow instabilities behind isolated roughness elements on re-entry capsules. 7TH EUROPEAN CONFERENCE FOR AERONAUTICS AND AEROSPACE SCIENCES (EUCASS), 03.-06. Juli 2017, Mailand, Italien.

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Official URL: http://www.eucass2017.eu/

Abstract

Laminar-turbulent transition caused by modal disturbance growth in the wake flow of isolated roughness elements on blunt re-entry capsules is studied numerically at typical cold hypersonic wind tunnel conditions. Two fundamentally different heat shield shapes are considered. On the sphere-cone forebody the wake flow of the roughness is exposed to an adverse pressure gradient, whereas the spherical heat shield exhibits a strongly favourable pressure gradient. The pressure gradient effects on the development of the stationary wake flow and its modal instability characteristics are discussed for various heights and diameters of the cylindrical roughness element. Regions of increased shear develop in its wake which persist longer in the adverse pressure gradient case. Consequently, the results of spatial two-dimensional eigenvalue analyses reveal that the unstable wake flow region extends much further downstream and the wake mode instabilities are considerably more amplified. The disturbance kinetic energy production terms are used to assess the contributions of the different shear-layer regions to the mode growth and its dependence on the pressure gradient

Item URL in elib:https://elib.dlr.de/114937/
Document Type:Conference or Workshop Item (Speech)
Title:Pressure gradient effects on wake flow instabilities behind isolated roughness elements on re-entry capsules
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Theiß, Alexanderalexander.theiss (at) dlr.deUNSPECIFIED
Leyh, SaschaUNSPECIFIEDUNSPECIFIED
Hein, StefanStefan.Hein (at) dlr.deUNSPECIFIED
Date:2017
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:re-entry capsule, blunt body, roughness-induced transition, LST-2D, pressure gradient effects
Event Title:7TH EUROPEAN CONFERENCE FOR AERONAUTICS AND AEROSPACE SCIENCES (EUCASS)
Event Location:Mailand, Italien
Event Type:international Conference
Event Dates:03.-06. Juli 2017
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
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > High Speed Configurations, GO
Deposited By: Bachmann, Barbara
Deposited On:23 Nov 2017 16:06
Last Modified:31 Jul 2019 20:12

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