Self-Similarity and Helical Symmetry of Various Vortex Wakes

Research output: Contribution to conferencePaperResearchpeer-review

162 Downloads (Pure)

Abstract

The present work examines the local structure and downstream evolution of both longitudinal vortexes behind the vortex generators and the helical tip vortices generated by the rotating 3-bladed rotor. Both wakes flow with thestrong longitudinal or helical vortices have been studied by stereo PIV measurements in a wind tunnel or a water flume accordingly. The vorticity field was calculated from the measured velocity fields. The downstream development of vortexlocal cores investigates by using self-similarity scaling arguments and local helical symmetry tests simultaneously. It wasanalyzed Batchelor’s vortex and 2-D vortex with a helical vortex to use a combined vortex model of the helical selfsimilarlyfor a comparison with the experimental data. The experimental study of the shape of both vortices was carried out to describe the downstream development of the expanding vortex core by the new combined vortex model based on the experimental observations triggered by previous studies of wakes behind vortex generators and rotors. It was established that the local helical symmetry with a simple correspondence between the axial and azimuthal velocity in the cores exists in all cross-sections along of both longitudinal and helical vortices. It is also found that the averaged vorticity profiles inside the core of both vortices are self-similar. This knowledge is important for the fundamental understanding of the vortex flows, as well as for the aspect of applications, for which parametric descriptions can be substantially reduced in terms of required time and cost by easing engineering models.
Original languageEnglish
Publication date2018
Number of pages7
Publication statusPublished - 2018
Event4th International Retreat on Vortical Flow and Aerodynamics (IRVA4) - Kutateladze Institute of Thermophysics, Novosibirsk, Russian Federation
Duration: 1 Oct 20183 Oct 2018

Conference

Conference4th International Retreat on Vortical Flow and Aerodynamics (IRVA4)
LocationKutateladze Institute of Thermophysics
CountryRussian Federation
CityNovosibirsk
Period01/10/201803/10/2018

Cite this

Kabardin, I. K., Mikkelsen, R. F., Naumov, I. V., Okulov, V. L., Sørensen, J. N., & Velte, C. M. (2018). Self-Similarity and Helical Symmetry of Various Vortex Wakes. Paper presented at 4th International Retreat on Vortical Flow and Aerodynamics (IRVA4) , Novosibirsk, Russian Federation.
Kabardin, I. K. ; Mikkelsen, R. F. ; Naumov, I.V. ; Okulov, V. L. ; Sørensen, J. N. ; Velte, C. M. / Self-Similarity and Helical Symmetry of Various Vortex Wakes. Paper presented at 4th International Retreat on Vortical Flow and Aerodynamics (IRVA4) , Novosibirsk, Russian Federation.7 p.
@conference{7a5648254acd4a8f9fcf6055b74de1ec,
title = "Self-Similarity and Helical Symmetry of Various Vortex Wakes",
abstract = "The present work examines the local structure and downstream evolution of both longitudinal vortexes behind the vortex generators and the helical tip vortices generated by the rotating 3-bladed rotor. Both wakes flow with thestrong longitudinal or helical vortices have been studied by stereo PIV measurements in a wind tunnel or a water flume accordingly. The vorticity field was calculated from the measured velocity fields. The downstream development of vortexlocal cores investigates by using self-similarity scaling arguments and local helical symmetry tests simultaneously. It wasanalyzed Batchelor’s vortex and 2-D vortex with a helical vortex to use a combined vortex model of the helical selfsimilarlyfor a comparison with the experimental data. The experimental study of the shape of both vortices was carried out to describe the downstream development of the expanding vortex core by the new combined vortex model based on the experimental observations triggered by previous studies of wakes behind vortex generators and rotors. It was established that the local helical symmetry with a simple correspondence between the axial and azimuthal velocity in the cores exists in all cross-sections along of both longitudinal and helical vortices. It is also found that the averaged vorticity profiles inside the core of both vortices are self-similar. This knowledge is important for the fundamental understanding of the vortex flows, as well as for the aspect of applications, for which parametric descriptions can be substantially reduced in terms of required time and cost by easing engineering models.",
author = "Kabardin, {I. K.} and Mikkelsen, {R. F.} and I.V. Naumov and Okulov, {V. L.} and S{\o}rensen, {J. N.} and Velte, {C. M.}",
year = "2018",
language = "English",
note = "4th International Retreat on Vortical Flow and Aerodynamics (IRVA4) ; Conference date: 01-10-2018 Through 03-10-2018",

}

Kabardin, IK, Mikkelsen, RF, Naumov, IV, Okulov, VL, Sørensen, JN & Velte, CM 2018, 'Self-Similarity and Helical Symmetry of Various Vortex Wakes', Paper presented at 4th International Retreat on Vortical Flow and Aerodynamics (IRVA4) , Novosibirsk, Russian Federation, 01/10/2018 - 03/10/2018.

Self-Similarity and Helical Symmetry of Various Vortex Wakes. / Kabardin, I. K. ; Mikkelsen, R. F.; Naumov, I.V.; Okulov, V. L.; Sørensen, J. N.; Velte, C. M.

2018. Paper presented at 4th International Retreat on Vortical Flow and Aerodynamics (IRVA4) , Novosibirsk, Russian Federation.

Research output: Contribution to conferencePaperResearchpeer-review

TY - CONF

T1 - Self-Similarity and Helical Symmetry of Various Vortex Wakes

AU - Kabardin, I. K.

AU - Mikkelsen, R. F.

AU - Naumov, I.V.

AU - Okulov, V. L.

AU - Sørensen, J. N.

AU - Velte, C. M.

PY - 2018

Y1 - 2018

N2 - The present work examines the local structure and downstream evolution of both longitudinal vortexes behind the vortex generators and the helical tip vortices generated by the rotating 3-bladed rotor. Both wakes flow with thestrong longitudinal or helical vortices have been studied by stereo PIV measurements in a wind tunnel or a water flume accordingly. The vorticity field was calculated from the measured velocity fields. The downstream development of vortexlocal cores investigates by using self-similarity scaling arguments and local helical symmetry tests simultaneously. It wasanalyzed Batchelor’s vortex and 2-D vortex with a helical vortex to use a combined vortex model of the helical selfsimilarlyfor a comparison with the experimental data. The experimental study of the shape of both vortices was carried out to describe the downstream development of the expanding vortex core by the new combined vortex model based on the experimental observations triggered by previous studies of wakes behind vortex generators and rotors. It was established that the local helical symmetry with a simple correspondence between the axial and azimuthal velocity in the cores exists in all cross-sections along of both longitudinal and helical vortices. It is also found that the averaged vorticity profiles inside the core of both vortices are self-similar. This knowledge is important for the fundamental understanding of the vortex flows, as well as for the aspect of applications, for which parametric descriptions can be substantially reduced in terms of required time and cost by easing engineering models.

AB - The present work examines the local structure and downstream evolution of both longitudinal vortexes behind the vortex generators and the helical tip vortices generated by the rotating 3-bladed rotor. Both wakes flow with thestrong longitudinal or helical vortices have been studied by stereo PIV measurements in a wind tunnel or a water flume accordingly. The vorticity field was calculated from the measured velocity fields. The downstream development of vortexlocal cores investigates by using self-similarity scaling arguments and local helical symmetry tests simultaneously. It wasanalyzed Batchelor’s vortex and 2-D vortex with a helical vortex to use a combined vortex model of the helical selfsimilarlyfor a comparison with the experimental data. The experimental study of the shape of both vortices was carried out to describe the downstream development of the expanding vortex core by the new combined vortex model based on the experimental observations triggered by previous studies of wakes behind vortex generators and rotors. It was established that the local helical symmetry with a simple correspondence between the axial and azimuthal velocity in the cores exists in all cross-sections along of both longitudinal and helical vortices. It is also found that the averaged vorticity profiles inside the core of both vortices are self-similar. This knowledge is important for the fundamental understanding of the vortex flows, as well as for the aspect of applications, for which parametric descriptions can be substantially reduced in terms of required time and cost by easing engineering models.

M3 - Paper

ER -

Kabardin IK, Mikkelsen RF, Naumov IV, Okulov VL, Sørensen JN, Velte CM. Self-Similarity and Helical Symmetry of Various Vortex Wakes. 2018. Paper presented at 4th International Retreat on Vortical Flow and Aerodynamics (IRVA4) , Novosibirsk, Russian Federation.