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Vortex dislocation in the near wake of a cylinder with span-wise variations in diameter

Ayancik, Fatma and Siegel, Lars and He, Guosheng and Henning, Arne and Mulleners, Karen (2022) Vortex dislocation in the near wake of a cylinder with span-wise variations in diameter. In: 20th International Symposium on Application of Laser and Imaging Techniques to Fluid Mechanics 2022, pp. 2731-2743. 20th International Symposium on Application of Laser and Imaging Techniques to Fluid Mechanics, 2022-07-11 - 2022-07-14, Lisbon, Portugal. ISBN 978-989-53637-0-4.

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Official URL: http://www.lisbon-lasersymposium.org/LXLASER2022

Abstract

We examined the evolution of three-dimensional vortex shedding patterns induced by spanwise variations of the cylinder diameter. Two distinct types of shedding patterns have identified through flow vi sualization: continuous (in-phase) oblique shedding where vortices shed with lower frequency stay attached to the vortices with higher frequency without any discontinuity or splitting and discontinuous (out-of-phase) shedding where the lower frequency vortices have no attachment to higher frequency vortices and vortex dislocation occurs. The dislocation seen in the flow is strongly influenced by th e span wi se ir regularities. We ob served a clear and strong in-phase spanwise vortex shedding for the three smooth cylinder configurations tested in the study. The tapered, bumps and steps configurations showed sections of strong coherent spanwise vortex shedding, and we identified hardly any coherent structures for the rib, sinusoidal, and helical configurations. Depending on the geometry and number of span wise irregularities, incoherent structures make difficult to determine the occurrence and location of vortex dislocations in the cylinder wake without a method that enables a reduction in the complexity. Here, we introduce a numerical approach that obtains the dominant structures of vortex shedding patterns by reducing the complexity in noisy data. The method maps the variations in the oblique shedding angle over time and provide quantitative conclusions on the intermittent occurrence and location of vortex dislocations in the 15 000 snapshots taken for each of the different cylinder geometries regardless of turbulence.

Item URL in elib:https://elib.dlr.de/189651/
Document Type:Conference or Workshop Item (Speech)
Title:Vortex dislocation in the near wake of a cylinder with span-wise variations in diameter
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Ayancik, FatmaInstitute of Mechanical Engineering, École polytechnique fédérale de Lausanne (EPFL), SwitzerlandUNSPECIFIEDUNSPECIFIED
Siegel, LarsUNSPECIFIEDhttps://orcid.org/0000-0002-5601-3826UNSPECIFIED
He, GuoshengUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Henning, ArneUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Mulleners, KarenUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Date:11 July 2022
Journal or Publication Title:20th International Symposium on Application of Laser and Imaging Techniques to Fluid Mechanics 2022
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Page Range:pp. 2731-2743
Editors:
EditorsEmailEditor's ORCID iDORCID Put Code
UNSPECIFIEDADAI - Association for the Development of Industrial Aerodynamics Center for Innovation, Technology and Policy Research IN+UNSPECIFIEDUNSPECIFIED
ISBN:978-989-53637-0-4
Status:Published
Keywords:vortex dislocation, intermittency, oblique shedding
Event Title:20th International Symposium on Application of Laser and Imaging Techniques to Fluid Mechanics
Event Location:Lisbon, Portugal
Event Type:international Conference
Event Start Date:11 July 2022
Event End Date:14 July 2022
Organizer:ADAI - Association for the Development of Industrial Aerodynamics
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Transport
HGF - Program Themes:Transport System
DLR - Research area:Transport
DLR - Program:V VS - Verkehrssystem
DLR - Research theme (Project):V - VMo4Orte - Vernetzte Mobilität für lebenswerte Orte
Location: Göttingen
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Ground Vehicles
Deposited By: Henning, Arne
Deposited On:08 Dec 2022 07:50
Last Modified:24 Apr 2024 20:50

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