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BY-NC-ND 3.0 license Open Access Published by Oldenbourg Wissenschaftsverlag November 24, 2016

Downstream relaxation of velocity profiles in pipe-flow with swirl disturbances

Stromabwärts-Relaxation von Geschwindigkeitsprofilen mit Drallstörungen
Simon Graner

Mr. Graner is responsible for optimizing verification processes and implementing novel statistical process control in Kamstrup's flow laboratory in Denmark. Mr. Graner studied mechanical engineering at Technische Universität München and at Pontificia Universidad Católica de Chile in Santiago de Chile. Prior to his current position Mr. Graner wrote his M.Sc. thesis on laser-Doppler velocimetry at Kamstrup in collaboration with the Chair of Aerodynamics and Fluidmechanics at Technische Universität München.

Kamstrup A/S, Industrivej 28, 8660 Skanderborg, Denmark, Tel.: +45 89 93 16 76

, Denis F. Hinz

Dr. Hinz is leading a team of engineers responsible for the flow laboratory at Kamstrup's headquarters in Denmark. His main research interests are experimental and computational fluid dynamics with focus on uncertainty quantification, optimization, and metrology. Prior to joining Kamstrup, Dr. Hinz worked at the Okinawa Institute of Science and Technology in Japan. He holds a Ph.D. in mechanical engineering from McGill University in Canada.

Kamstrup A/S, Industrivej 28, 8660 Skanderborg, Denmark, Tel.: +45 89 93 16 13

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and Christian Breitsamter

Prof. Breitsamter is head of the Aircraft and Spacecraft Aerodynamics Division at the Chair of Aerodynamics and Fluidmechanics. Research projects are on wind tunnel testing of aircraft and rotorcraft configurations with a special emphasis on flow control including a variety of optical measurement techniques. A further focus is on the development of aeroelastic simulation tools and analysis of complex vortex dominated flows.

Technical University of Munich, Chair of Aerodynamics and Fluidmechanics, Boltzmannstrasse 15, 85748 Garching, Germany

From the journal tm - Technisches Messen

Abstract

We study characteristic flow patterns downstream of a standardized swirl disturbance generator using laser-Doppler velocimetry (LDV). To investigate the spatial development of flow patterns, we conduct LDV measurements in cross-sections located at various distances downstream from the swirl disturbance generator. Focusing on velocity profiles, decay of swirl, and performance indicators used to describe the characteristic shape of the velocity profiles, we systematically compare the experimental results with available references and various theories for decay of swirl disturbances. We find that the standardized swirl disturbance generator provides exponentially decaying swirling flow that is best captured by the theory of Steenbergen and Voskamp[1]. In addition, deviations from the axial reference profile caused by the swirl disturber persist for long downstream distances. In particular, our results suggest that the peakness factor relaxes linearly towards the fully-developed state.

Zusammenfassung

Wir untersuchen charakteristische Strömungsmuster hinter einem standardisierten Drallgenerator mittels Laser-Doppler-Anemometrie (LDA). Um die räumliche Entwicklung von Strömungsmustern zu untersuchen, führen wir LDA-Messungen in Querschnitten in unterschiedlichen Abständen stromabwärts des Drallgenerators durch. Mit Fokus auf Geschwindigkeitsprofilen, dem Verfall von Drallstörungen, und Performance-Indikatoren, um die charakteristische Form der Geschwindigkeitsprofile zu beschreiben, vergleichen wir systematisch die experimentellen Ergebnisse mit verfügbaren Referenzen und verschiedenen Theorien für den Zerfall von Wirbelstörungen. Unsere Ergebnisse zeigen, dass der standardisierte Drallgenerator exponentiell abklingende Drallströmungen erzeugt, die am besten durch die Theorie von Steenbergen and Voskamp erfasst wird. Außerdem können die durch den Störkörper verursachten Abweichungen vom axialen Referenzprofil lange stromabwärts nachgewiesen werden. Insbesondere legen unsere Ergebnisse nahe, dass der sogenannte Peakness-Faktor linear zu einer voll entwickelten Strömung relaxiert.

Funding statement: Kampstrup A/S

About the authors

Simon Graner

Mr. Graner is responsible for optimizing verification processes and implementing novel statistical process control in Kamstrup's flow laboratory in Denmark. Mr. Graner studied mechanical engineering at Technische Universität München and at Pontificia Universidad Católica de Chile in Santiago de Chile. Prior to his current position Mr. Graner wrote his M.Sc. thesis on laser-Doppler velocimetry at Kamstrup in collaboration with the Chair of Aerodynamics and Fluidmechanics at Technische Universität München.

Kamstrup A/S, Industrivej 28, 8660 Skanderborg, Denmark, Tel.: +45 89 93 16 76

Denis F. Hinz

Dr. Hinz is leading a team of engineers responsible for the flow laboratory at Kamstrup's headquarters in Denmark. His main research interests are experimental and computational fluid dynamics with focus on uncertainty quantification, optimization, and metrology. Prior to joining Kamstrup, Dr. Hinz worked at the Okinawa Institute of Science and Technology in Japan. He holds a Ph.D. in mechanical engineering from McGill University in Canada.

Kamstrup A/S, Industrivej 28, 8660 Skanderborg, Denmark, Tel.: +45 89 93 16 13

Christian Breitsamter

Prof. Breitsamter is head of the Aircraft and Spacecraft Aerodynamics Division at the Chair of Aerodynamics and Fluidmechanics. Research projects are on wind tunnel testing of aircraft and rotorcraft configurations with a special emphasis on flow control including a variety of optical measurement techniques. A further focus is on the development of aeroelastic simulation tools and analysis of complex vortex dominated flows.

Technical University of Munich, Chair of Aerodynamics and Fluidmechanics, Boltzmannstrasse 15, 85748 Garching, Germany

Acknowledgement

DFH acknowledges the support of Mario Turiso in preparing the manuscript. DFH and SG would like to thank Dr. Jens Lykke Sørensen for providing valuable feedback on earlier versions of the manuscript and Preben Mønsted Nielsen, Salim Umar, Karsten Lundsgaard and Thor Marum for their great technical support.

Received: 2016-8-11
Revised: 2016-10-7
Accepted: 2016-10-12
Published Online: 2016-11-24
Published in Print: 2016-12-28

©2016 Kampstrup A/S, published by De Gruyter.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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