Turbulence structure and unsteadiness in a separation-reattachment flow

Masaru Kiya, Kyuro Sasaki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A wind tunnel experiment has been performed to obtain the unsteady nature of flow in a turbulent separation bubble formed at the leading edge of a blunt plate with right-angled corners. Reynolds number based on the free-stream velocity and the thickness of the plate was of the order of 10,000. The reverse-flow intermittency Ir was found to be the error function of the time-mean value of the local longitudinal velocity divided by its rms value in most of the separation bubble. This was because the longitudinal velocity fluctuation was approximately Gaussian except near the outer edge of the separated shear layer. The frequency at which the local flow changes its direction was a fairly unique function of Ir, attaining a maximum of about twice the central frequency of shedding of large-scale vortices from the reattaching zone. On the other hand, the bursting frequency in the relaxing boundary layer downstream of the separation bubble was equal to the vortex-shedding frequency. These features suggested a mechanism by which the heat-transfer rate attains a maximum near the time-mean reattachment line.
Original languageEnglish
Title of host publicationProceedings of 5th Symposium on Turbulent Shear Flows (Ithaca, NY, USA)
PublisherSpringer-Verlag Berlin Heidelberg
Pages5.7-5.12
Number of pages6
ISBN (Print)978-3-642-71435-1
Publication statusPublished - Aug 7 1985

Fingerprint

Turbulence
Vortex shedding
Wind tunnels
Boundary layers
Vortex flow
Reynolds number
Heat transfer
Experiments
Direction compound

All Science Journal Classification (ASJC) codes

  • Fluid Flow and Transfer Processes

Cite this

Kiya, M., & Sasaki, K. (1985). Turbulence structure and unsteadiness in a separation-reattachment flow. In Proceedings of 5th Symposium on Turbulent Shear Flows (Ithaca, NY, USA) (pp. 5.7-5.12). Springer-Verlag Berlin Heidelberg.

Turbulence structure and unsteadiness in a separation-reattachment flow. / Kiya, Masaru; Sasaki, Kyuro.

Proceedings of 5th Symposium on Turbulent Shear Flows (Ithaca, NY, USA). Springer-Verlag Berlin Heidelberg, 1985. p. 5.7-5.12.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Kiya, M & Sasaki, K 1985, Turbulence structure and unsteadiness in a separation-reattachment flow. in Proceedings of 5th Symposium on Turbulent Shear Flows (Ithaca, NY, USA). Springer-Verlag Berlin Heidelberg, pp. 5.7-5.12.
Kiya M, Sasaki K. Turbulence structure and unsteadiness in a separation-reattachment flow. In Proceedings of 5th Symposium on Turbulent Shear Flows (Ithaca, NY, USA). Springer-Verlag Berlin Heidelberg. 1985. p. 5.7-5.12
Kiya, Masaru ; Sasaki, Kyuro. / Turbulence structure and unsteadiness in a separation-reattachment flow. Proceedings of 5th Symposium on Turbulent Shear Flows (Ithaca, NY, USA). Springer-Verlag Berlin Heidelberg, 1985. pp. 5.7-5.12
@inproceedings{b967142664524af6b0317d6f60e0126e,
title = "Turbulence structure and unsteadiness in a separation-reattachment flow",
abstract = "A wind tunnel experiment has been performed to obtain the unsteady nature of flow in a turbulent separation bubble formed at the leading edge of a blunt plate with right-angled corners. Reynolds number based on the free-stream velocity and the thickness of the plate was of the order of 10,000. The reverse-flow intermittency Ir was found to be the error function of the time-mean value of the local longitudinal velocity divided by its rms value in most of the separation bubble. This was because the longitudinal velocity fluctuation was approximately Gaussian except near the outer edge of the separated shear layer. The frequency at which the local flow changes its direction was a fairly unique function of Ir, attaining a maximum of about twice the central frequency of shedding of large-scale vortices from the reattaching zone. On the other hand, the bursting frequency in the relaxing boundary layer downstream of the separation bubble was equal to the vortex-shedding frequency. These features suggested a mechanism by which the heat-transfer rate attains a maximum near the time-mean reattachment line.",
author = "Masaru Kiya and Kyuro Sasaki",
year = "1985",
month = "8",
day = "7",
language = "English",
isbn = "978-3-642-71435-1",
pages = "5.7--5.12",
booktitle = "Proceedings of 5th Symposium on Turbulent Shear Flows (Ithaca, NY, USA)",
publisher = "Springer-Verlag Berlin Heidelberg",

}

TY - GEN

T1 - Turbulence structure and unsteadiness in a separation-reattachment flow

AU - Kiya, Masaru

AU - Sasaki, Kyuro

PY - 1985/8/7

Y1 - 1985/8/7

N2 - A wind tunnel experiment has been performed to obtain the unsteady nature of flow in a turbulent separation bubble formed at the leading edge of a blunt plate with right-angled corners. Reynolds number based on the free-stream velocity and the thickness of the plate was of the order of 10,000. The reverse-flow intermittency Ir was found to be the error function of the time-mean value of the local longitudinal velocity divided by its rms value in most of the separation bubble. This was because the longitudinal velocity fluctuation was approximately Gaussian except near the outer edge of the separated shear layer. The frequency at which the local flow changes its direction was a fairly unique function of Ir, attaining a maximum of about twice the central frequency of shedding of large-scale vortices from the reattaching zone. On the other hand, the bursting frequency in the relaxing boundary layer downstream of the separation bubble was equal to the vortex-shedding frequency. These features suggested a mechanism by which the heat-transfer rate attains a maximum near the time-mean reattachment line.

AB - A wind tunnel experiment has been performed to obtain the unsteady nature of flow in a turbulent separation bubble formed at the leading edge of a blunt plate with right-angled corners. Reynolds number based on the free-stream velocity and the thickness of the plate was of the order of 10,000. The reverse-flow intermittency Ir was found to be the error function of the time-mean value of the local longitudinal velocity divided by its rms value in most of the separation bubble. This was because the longitudinal velocity fluctuation was approximately Gaussian except near the outer edge of the separated shear layer. The frequency at which the local flow changes its direction was a fairly unique function of Ir, attaining a maximum of about twice the central frequency of shedding of large-scale vortices from the reattaching zone. On the other hand, the bursting frequency in the relaxing boundary layer downstream of the separation bubble was equal to the vortex-shedding frequency. These features suggested a mechanism by which the heat-transfer rate attains a maximum near the time-mean reattachment line.

M3 - Conference contribution

SN - 978-3-642-71435-1

SP - 5.7-5.12

BT - Proceedings of 5th Symposium on Turbulent Shear Flows (Ithaca, NY, USA)

PB - Springer-Verlag Berlin Heidelberg

ER -