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

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• 作者：B. Alveroglu^a ; ^{ba123@le.ac.uk} ; A. Segalini^b ; S.J. Garrett^c
• 关键词：Roughness ; BEK family ; Energy
• 刊名：European Journal of Mechanics - B/Fluids
• 出版年：2017
• 出版时间：January-February 2017
• 年：2017
• 卷：61
• 期：part_P2
• 页码：310-315
• 全文大小：570 K
• 卷排序：61

文摘

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 discretization 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 destabilizing. In the case of the viscous Type II instability mode, the results predict a destabilization effect of radially-anisotropic roughness (concentric grooves) on both flows, whereas both azimuthally-anisotropic roughness and isotropic roughness have a stabilization effect. The results presented here confirm the results of our prior linear stability analyses.