Drag reduction of turbulent flows in a curved pipe due to the swirling instability

Toshïro Takami; Shinichiro Yanase; Yuichi Maruyama; Keisuke Araki

doi:10.1299/kikaib.66.997

Drag reduction of turbulent flows in a curved pipe due to the swirling instability

Toshïro Takami, Shinichiro Yanase, Yuichi Maruyama, Keisuke Araki

Research output: Contribution to journal › Article

Abstract

The effect of the introduction of swirling motion into turbulent flow in a curved pipe is studied experimentally. The friction of the flow in a straight pipe is known to increase as the introduced swirling motion intensifies. In the present study, it is found that the friction in a curved pipe is reduced when weak swirling motion is provided. In order to investigate this drag reduction, velocity distributions are measured at some cross sections in the curved pipe by use of the rotating probe technique with an inclined hot-wire. Detailed measurements of the velocity field reveal that interesting swingback phenomena appear as the vortical flow structure develops from the entrance of the pipe, which may cause the drag reduction in case of weak swirls.

Original language	English
Pages (from-to)	997-1003
Number of pages	7
Journal	Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
Volume	66
Issue number	644
DOIs	https://doi.org/10.1299/kikaib.66.997
Publication status	Published - Apr 2000
Externally published	Yes

Keywords

Curved pipe
Drag reduction
Secondary flow
Swirling flow
Three-dimensional flow
Turbulent flow
Vortex

ASJC Scopus subject areas

Condensed Matter Physics
Mechanical Engineering

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Takami, T., Yanase, S., Maruyama, Y., & Araki, K. (2000). Drag reduction of turbulent flows in a curved pipe due to the swirling instability. Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B, 66(644), 997-1003. https://doi.org/10.1299/kikaib.66.997

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abstract = "The effect of the introduction of swirling motion into turbulent flow in a curved pipe is studied experimentally. The friction of the flow in a straight pipe is known to increase as the introduced swirling motion intensifies. In the present study, it is found that the friction in a curved pipe is reduced when weak swirling motion is provided. In order to investigate this drag reduction, velocity distributions are measured at some cross sections in the curved pipe by use of the rotating probe technique with an inclined hot-wire. Detailed measurements of the velocity field reveal that interesting swingback phenomena appear as the vortical flow structure develops from the entrance of the pipe, which may cause the drag reduction in case of weak swirls.",

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AU - Takami, Toshïro

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AU - Araki, Keisuke

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N2 - The effect of the introduction of swirling motion into turbulent flow in a curved pipe is studied experimentally. The friction of the flow in a straight pipe is known to increase as the introduced swirling motion intensifies. In the present study, it is found that the friction in a curved pipe is reduced when weak swirling motion is provided. In order to investigate this drag reduction, velocity distributions are measured at some cross sections in the curved pipe by use of the rotating probe technique with an inclined hot-wire. Detailed measurements of the velocity field reveal that interesting swingback phenomena appear as the vortical flow structure develops from the entrance of the pipe, which may cause the drag reduction in case of weak swirls.

AB - The effect of the introduction of swirling motion into turbulent flow in a curved pipe is studied experimentally. The friction of the flow in a straight pipe is known to increase as the introduced swirling motion intensifies. In the present study, it is found that the friction in a curved pipe is reduced when weak swirling motion is provided. In order to investigate this drag reduction, velocity distributions are measured at some cross sections in the curved pipe by use of the rotating probe technique with an inclined hot-wire. Detailed measurements of the velocity field reveal that interesting swingback phenomena appear as the vortical flow structure develops from the entrance of the pipe, which may cause the drag reduction in case of weak swirls.

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