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, 11.-14. Juli 2022, 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/ | ||||||||||||||||||||||||
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Document Type: | Conference or Workshop Item (Speech) | ||||||||||||||||||||||||
Title: | Vortex dislocation in the near wake of a cylinder with span-wise variations in diameter | ||||||||||||||||||||||||
Authors: |
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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: |
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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 Dates: | 11.-14. Juli 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: | 08 Dec 2022 07:50 |
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