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

作者：Alveroglu B^*; Segalini A; Garrett S J

来源：European Journal of Mechanics - B: Fluids , 2017, 61: 310-315.

DOI：10.1016/j.euromechflu.2016.09.006

• Roughness
• BEK family
• Energy

An energy balance equation for the three-dimensional Bodewadt 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 Bodewadt 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.

• 出版日期2017-2