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Surface temperature effects on boundary-layer transition at various subsonic Mach numbers

Costantini, Marco and Risius, Steffen and Klein, Christian (2018) Surface temperature effects on boundary-layer transition at various subsonic Mach numbers. In: 21th STAB/DGLR Symposium on New Results in Numerical and Experimental Fluid Mechanics, pp. 54-55. 21. STAB/DGLR Symposium 2018, 06.-07. Nov. 2018, Darmstadt, Deutschland.

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Official URL: https://www.sla.tu-darmstadt.de/stab_2018/stab2018_home.de.jsp

Abstract

The effect on transition of variations in Mach number and pressure gradient was systematically studied in the present experimental work in combination with the influence of a non-adiabatic surface. The investigations were carried out in a (quasi-) two-dimensional flow at Mach numbers from M = 0.35 to 0.77 and large chord Reynolds numbers with various streamwise pressure gradients and wall temperature ratios. The examined test conditions are relevant for the climb and cruise phases of transport aircraft employing Natural Laminar Flow surfaces with zero to moderate sweep angles, on which the predominant mechanism leading to transition is the amplification of Tollmien-Schlichting waves. The experiments were conducted in the low-turbulence Cryogenic Ludwieg-Tube Göttingen on a two-dimensional flat-plate configuration designed for an essentially uniform pressure gradient on the model upper side. The model was instrumented with a Temperature-Sensitive Paint (TSP) to measure globally and non-intrusively the surface temperature and thus the boundary-layer transition, and with pressure taps to measure the surface pressure. A pronounced influence of a variation in the wall temperature ratio on boundary-layer transition was observed for all Mach numbers examined in the present study. The measured transition locations were correlated with the results of linear local stability analysis, thus providing transition N-factors for the various combinations of wall temperature ratio, Mach number, Reynolds number and pressure gradient considered in this work.

Item URL in elib:https://elib.dlr.de/122990/
Document Type:Conference or Workshop Item (Speech)
Title:Surface temperature effects on boundary-layer transition at various subsonic Mach numbers
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Costantini, MarcoMarco.Costantini (at) dlr.dehttps://orcid.org/0000-0003-0642-0199
Risius, Steffensteffen.risius (at) dlr.dehttps://orcid.org/0000-0002-5530-9609
Klein, Christianchristian.klein (at) dlr.deUNSPECIFIED
Date:November 2018
Journal or Publication Title:21th STAB/DGLR Symposium on New Results in Numerical and Experimental Fluid Mechanics
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Page Range:pp. 54-55
Status:Published
Keywords:Transition, Non-adiabatic surface, Temperature-sensitive paint, Boundary layer, Natural laminar flow, TSP
Event Title:21. STAB/DGLR Symposium 2018
Event Location:Darmstadt, Deutschland
Event Type:national Conference
Event Dates:06.-07. Nov. 2018
Organizer:Technische Universität Darmstadt, STAB
Institution:Deutsches Zentrum für Luft- und Raumfahrt e.V.
Department:AS-EXV
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 - Simulation and Validation
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Experimental Methods, GO
Deposited By: Micknaus, Ilka
Deposited On:03 Dec 2018 14:40
Last Modified:03 Dec 2018 14:40

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