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Excitation of vortex meandering in shear flow

Schröttle, Josef and Dörnbrack, Andreas and Schumann, Ulrich (2015) Excitation of vortex meandering in shear flow. Fluid Dynamics Research, 47 (3), pp. 1-17. Institute of Physics (IOP) Publishing. DOI: 10.1088/0169-5983/47/3/035508 ISSN 0169-5983

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Official URL: http://dx.doi.org/10.1088/0169-5983/47/3/035508

Abstract

This paper investigates the evolution of a streamwise aligned columnar vortex with vorticity ω in an axial background shear of magnitude Ω by means of linear stability analysis and numerical simulations. A long wave mode of vorticity normal to the plane spanned by the background shear vector Ω and the vorticity of the vortex are excited by an instability. The stationary wave modes of the vertical and lateral vorticity are amplified. In order to form a helical vortex, the lateral and vertical vorticity can be phase shifted by half a wavelength. The linear and nonlinear evolutions of the vortex in the shear flow are studied numerically. Linearized simulations confirm the results of the stability analysis. The nonlinear simulations reveal further evolution of the helix in the shear flow. The linearly excited mode persists in co-existence with evolving smaller scale instabilities until the flow becomes fully turbulent at the time of O(100 Ω−1). Turbulent mixing dampens the amplifying mode. The described phenomenon of vortex meandering may serve as an alternative explanation for the excitation of wind turbine wake meandering in the atmospheric boundary layer.

Item URL in elib:https://elib.dlr.de/96171/
Document Type:Article
Title:Excitation of vortex meandering in shear flow
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Schröttle, JosefDLR, IPAUNSPECIFIED
Dörnbrack, AndreasDLR, IPAUNSPECIFIED
Schumann, UlrichDLR, IPAUNSPECIFIED
Date:April 2015
Journal or Publication Title:Fluid Dynamics Research
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:47
DOI :10.1088/0169-5983/47/3/035508
Page Range:pp. 1-17
Publisher:Institute of Physics (IOP) Publishing
ISSN:0169-5983
Status:Published
Keywords:atmospheric boundary layer, wind energy, wake vortex, meandering
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:other
DLR - Research area:Energy
DLR - Program:E SF - Solar research
DLR - Research theme (Project):E - Wind Energy (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Transport Meteorology
Institute of Atmospheric Physics
Deposited By: Ziegele, Brigitte
Deposited On:05 May 2015 15:45
Last Modified:06 Sep 2019 15:25

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