Flow around a hemisphere-cylinder at high angle of attack and low Reynolds number. Part I: Experimental and numerical investigation

Le Clainche Martinez, Soledad and Jingyun I., Li and Theofilis, Vassilis and Soria, Julio (2015). Flow around a hemisphere-cylinder at high angle of attack and low Reynolds number. Part I: Experimental and numerical investigation. "Aerospace Science and Technology", v. 44 ; pp. 77-87. ISSN 1270-9638. https://doi.org/10.1016/j.ast.2014.03.017.

Description

Title: Flow around a hemisphere-cylinder at high angle of attack and low Reynolds number. Part I: Experimental and numerical investigation
Author/s:
  • Le Clainche Martinez, Soledad
  • Jingyun I., Li
  • Theofilis, Vassilis
  • Soria, Julio
Item Type: Article
Título de Revista/Publicación: Aerospace Science and Technology
Date: 2015
ISSN: 1270-9638
Volume: 44
Subjects:
Freetext Keywords: Hemisphere-cylinder; Flow separation; Global instability; POD; DMD; Flow topology
Faculty: E.T.S. de Ingeniería Aeronáutica y del Espacio (UPM)
Department: Matemática Aplicada a la Ingeniería Aeroespacial
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Three-dimensional Direct Numerical Simulations combined with Particle Image Velocimetry experiments have been performed on a hemisphere-cylinder at Reynolds number 1000 and angle of attack 20◦. At these flow conditions, a pair of vortices, so-called “horn” vortices, are found to be associated with flow separation. In order to understand the highly complex phenomena associated with this fully threedimensional massively separated flow, different structural analysis techniques have been employed: Proper Orthogonal and Dynamic Mode Decompositions, POD and DMD, respectively, as well as criticalpoint theory. A single dominant frequency associated with the von Karman vortex shedding has been identified in both the experimental and the numerical results. POD and DMD modes associated with this frequency were recovered in the analysis. Flow separation was also found to be intrinsically linked to the observed modes. On the other hand, critical-point theory has been applied in order to highlight possible links of the topology patterns over the surface of the body with the computed modes. Critical points and separation lines on the body surface show in detail the presence of different flow patterns in the base flow: a three-dimensional separation bubble and two pairs of unsteady vortices systems, the horn vortices, mentioned before, and the so-called “leeward” vortices. The horn vortices emerge perpendicularly from the body surface at the separation region. On the other hand, the leeward vortices are originated downstream of the separation bubble, as a result of the boundary layer separation. The frequencies associated with these vortical structures have been quantified.

Funding Projects

TypeCodeAcronymLeaderTitle
FP7247651ICOMASEFUniversidad Politécnica de MadridInstability and control of massively separated flows
Government of SpainTRA2012-34148MeRenAlUniversidad Politécnica de MadridMejoras del Rendimiento aerodinámico de alas mediante control de mecanismos de inestabilidad global

More information

Item ID: 40897
DC Identifier: http://oa.upm.es/40897/
OAI Identifier: oai:oa.upm.es:40897
DOI: 10.1016/j.ast.2014.03.017
Official URL: http://www.sciencedirect.com/science/article/pii/S1270963814000844
Deposited by: Memoria Investigacion
Deposited on: 29 Sep 2016 10:16
Last Modified: 29 Sep 2016 10:49
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