An energy analysis of convective instabilities of the Bödewadt and Ekman boundary layers over rough surfaces

B. Alveroglu; A. Segalini; S. J. Garrett

An energy analysis of convective instabilities of the Bödewadt and Ekman boundary layers over rough surfaces

B. Alveroglu^*, A. Segalini, S. J. Garrett

^*Corresponding author for this work

College of Engineering and Physical Sciences

Research output: Chapter in Book/Published conference output › Conference publication

Abstract

An energy balance equation for the three-dimensional Bödewadt and Ekman layers of the so called “BEK family" of rotating boundary-layer flows is derived. A Chebyshev discretisation method is used to solve the equations and investigate the effect of surface roughness on the physical mechanisms of transition. All roughness types lead to a stabilization of the Type I (cross-flow) instability mode for both flows, with the exception of azimuthally-anisotropic roughness (radial grooves) within the Bödewadt layer which is destabilising. In the case of the viscous Type II instability mode, the results predict a destabilisation effect of radially-anisotropic roughness (concentric grooves) on both flows, whereas both azimuthally-anisotropic roughness and isotropic roughness have a stabilisation effect. The results presented here confirm the results of our prior linear stability analyses.

Original language	English
Title of host publication	Proceedings of the 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery
Publication status	Published - 2019
Event	16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016 - Honolulu, United States Duration: 10 Apr 2016 → 15 Apr 2016

Conference

Conference	16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016
Country/Territory	United States
City	Honolulu
Period	10/04/16 → 15/04/16

Bibliographical note

Funding Information:
This research used the ALICE High Performance Computing Facility at the University of Leicester. BA wishes to acknowledge financial support from Ministry of National Education, Republic of Turkey. SJG is supported by a Senior Research Fellowship of the Royal Academy of Engineering, funded by the Leverhulme Trust.

Publisher Copyright:
© Open Archives of the 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016. All rights reserved.

Keywords

BEK family
Energy
Roughness

Access to Document

https://hal.parisnanterre.fr/ISROMAC2016/hal-01879370

Cite this

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title = "An energy analysis of convective instabilities of the B{\"o}dewadt and Ekman boundary layers over rough surfaces",

abstract = "An energy balance equation for the three-dimensional B{\"o}dewadt and Ekman layers of the so called “BEK family{"} of rotating boundary-layer flows is derived. A Chebyshev discretisation method is used to solve the equations and investigate the effect of surface roughness on the physical mechanisms of transition. All roughness types lead to a stabilization of the Type I (cross-flow) instability mode for both flows, with the exception of azimuthally-anisotropic roughness (radial grooves) within the B{\"o}dewadt layer which is destabilising. In the case of the viscous Type II instability mode, the results predict a destabilisation effect of radially-anisotropic roughness (concentric grooves) on both flows, whereas both azimuthally-anisotropic roughness and isotropic roughness have a stabilisation effect. The results presented here confirm the results of our prior linear stability analyses.",

keywords = "BEK family, Energy, Roughness",

author = "B. Alveroglu and A. Segalini and Garrett, {S. J.}",

note = "Funding Information: This research used the ALICE High Performance Computing Facility at the University of Leicester. BA wishes to acknowledge financial support from Ministry of National Education, Republic of Turkey. SJG is supported by a Senior Research Fellowship of the Royal Academy of Engineering, funded by the Leverhulme Trust. Publisher Copyright: {\textcopyright} Open Archives of the 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016. All rights reserved.; 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016 ; Conference date: 10-04-2016 Through 15-04-2016",

year = "2019",

language = "English",

booktitle = "Proceedings of the 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery",

}

Alveroglu, B, Segalini, A & Garrett, SJ 2019, An energy analysis of convective instabilities of the Bödewadt and Ekman boundary layers over rough surfaces. in Proceedings of the 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery. 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016, Honolulu, United States, 10/04/16. <https://hal.parisnanterre.fr/ISROMAC2016/hal-01879370>

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T1 - An energy analysis of convective instabilities of the Bödewadt and Ekman boundary layers over rough surfaces

AU - Alveroglu, B.

AU - Segalini, A.

AU - Garrett, S. J.

N1 - Funding Information: This research used the ALICE High Performance Computing Facility at the University of Leicester. BA wishes to acknowledge financial support from Ministry of National Education, Republic of Turkey. SJG is supported by a Senior Research Fellowship of the Royal Academy of Engineering, funded by the Leverhulme Trust. Publisher Copyright: © Open Archives of the 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016. All rights reserved.

PY - 2019

Y1 - 2019

N2 - An energy balance equation for the three-dimensional Bödewadt and Ekman layers of the so called “BEK family" of rotating boundary-layer flows is derived. A Chebyshev discretisation method is used to solve the equations and investigate the effect of surface roughness on the physical mechanisms of transition. All roughness types lead to a stabilization of the Type I (cross-flow) instability mode for both flows, with the exception of azimuthally-anisotropic roughness (radial grooves) within the Bödewadt layer which is destabilising. In the case of the viscous Type II instability mode, the results predict a destabilisation effect of radially-anisotropic roughness (concentric grooves) on both flows, whereas both azimuthally-anisotropic roughness and isotropic roughness have a stabilisation effect. The results presented here confirm the results of our prior linear stability analyses.

AB - An energy balance equation for the three-dimensional Bödewadt and Ekman layers of the so called “BEK family" of rotating boundary-layer flows is derived. A Chebyshev discretisation method is used to solve the equations and investigate the effect of surface roughness on the physical mechanisms of transition. All roughness types lead to a stabilization of the Type I (cross-flow) instability mode for both flows, with the exception of azimuthally-anisotropic roughness (radial grooves) within the Bödewadt layer which is destabilising. In the case of the viscous Type II instability mode, the results predict a destabilisation effect of radially-anisotropic roughness (concentric grooves) on both flows, whereas both azimuthally-anisotropic roughness and isotropic roughness have a stabilisation effect. The results presented here confirm the results of our prior linear stability analyses.

KW - BEK family

KW - Energy

KW - Roughness

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M3 - Conference publication

BT - Proceedings of the 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery

T2 - 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016

Y2 - 10 April 2016 through 15 April 2016

ER -

An energy analysis of convective instabilities of the Bödewadt and Ekman boundary layers over rough surfaces

Abstract

Conference

Bibliographical note

Keywords

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