On the Origins of Three-Dimensionality And Unsteadiness in the Laminar Separation Bubble

Theofilis, Vassilios and Hein, Stefan and Dallmann, Uwe Ch. (2000). On the Origins of Three-Dimensionality And Unsteadiness in the Laminar Separation Bubble. "Philosophical Transactions of the Royal Society A", v. 358 (n. 1777); pp. 3229-3246. ISSN 1364-503X. https://doi.org/10.1098/rsta.2000.0706.

Description

Title: On the Origins of Three-Dimensionality And Unsteadiness in the Laminar Separation Bubble
Author/s:
  • Theofilis, Vassilios
  • Hein, Stefan
  • Dallmann, Uwe Ch.
Item Type: Article
Título de Revista/Publicación: Philosophical Transactions of the Royal Society A
Date: December 2000
ISSN: 1364-503X
Volume: 358
Subjects:
Faculty: E.T.S.I. Aeronáuticos (UPM)
Department: Motopropulsión y Termofluidodinámica [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

We analyse the three-dimensional non-parallel instability mechanisms responsible for transition to turbulence in regions of recirculating steady laminar two-dimensional incompressible separation bubble ®ow in a twofold manner. First, we revisit the problem of Tollmien{Schlichting (TS)-like disturbances and we demonstrate, for the ­ rst time for this type of ®ow, excellent agreement between the parabolized stabil- ity equation results and those of independently performed direct numerical simula- tions. Second, we perform a partial-derivative eigenvalue problem stability analysis by discretizing the two spatial directions on which the basic ®ow depends, precluding TS-like waves from entering the calculation domain. A new two-dimensional set of global ampli­ ed instability modes is thus discovered. In order to prove earlier topo- logical conjectures about the ®ow structural changes occurring prior to the onset of bubble unsteadiness, we reconstruct the total ®ow­ eld by linear superposition of the steady two-dimensional basic ®ow and the new most-ampli­ ed global eigenmodes. In the parameter range investigated, the result is a bifurcation into a three-dimensional ®ow­ eld in which the separation line remains una¬ected while the primary reattach- ment line becomes three dimensional, in line with the analogous result of a multitude of experimental observations.

More information

Item ID: 10442
DC Identifier: http://oa.upm.es/10442/
OAI Identifier: oai:oa.upm.es:10442
DOI: 10.1098/rsta.2000.0706
Official URL: http://rsta.royalsocietypublishing.org/content/358/1777/3229
Deposited by: Memoria Investigacion
Deposited on: 05 Mar 2012 12:27
Last Modified: 20 Apr 2016 18:39
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