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Nonlinear Nonlocal Instability Analyses of Transitional Separation Bubbles

Hein, S. (2004) Nonlinear Nonlocal Instability Analyses of Transitional Separation Bubbles. NATO RTO AVT-111, Specialists' Meeting on Enhancement of NATO Military Flight Vehicle Performance by Management of Interacting Boundary Layer Transition and Separation, 2004-10-04 - 2004-10-07, Prague (Czech Republic).

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Abstract

The linear and nonlinear instability properties of steady laminar two-dimensional incompressible boundary-layer flows with thin separation bubbles are analyzed by means of nonlocal instability theory based on the parabolized stability equations (PSE). The results are compared to data from a direct numerical simulation (DNS). Good to excellent agreement is found in the linear as well as the moderately nonlinear regime, clearly demonstrating that PSE methods are an appropriate instability analysis tool for this type of flow as well. Moreover, a vortex-shedding Strouhal number available in literature and reportedly being independent of Reynolds number and pressure gradient is verified. This Strouhal number, obtained by time-accurate Navier-Stokes simulations, is in line with the Strouhal numbers of the most amplified two-dimensional disturbances obtained from the instability analysis of the two laminar separated flows considered here.

Document Type:Conference or Workshop Item (Paper)
Title:Nonlinear Nonlocal Instability Analyses of Transitional Separation Bubbles
Authors:
AuthorsInstitution or Email of Authors
Hein, S.UNSPECIFIED
Date:2004
Refereed publication:Yes
In ISI Web of Science:No
Status:Published
Keywords:transitional separation bubble, convective instability, linear and nonlinear nonlocal instability analysis, NOLOT/PSE, comparison with DNS
Event Title:NATO RTO AVT-111, Specialists' Meeting on Enhancement of NATO Military Flight Vehicle Performance by Management of Interacting Boundary Layer Transition and Separation
Event Location:Prague (Czech Republic)
Event Type:international Conference
Event Dates:2004-10-04 - 2004-10-07
Organizer:RTO
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Helicopters
Deposited By: elib DLR-Beauftragter
Deposited On:24 Aug 2007
Last Modified:14 Jan 2010 19:35

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