2015/10/31 by Xiaojue Zhu, Rodolfo Ostilla–Mónico, Rodolfo Ostilla Mónico +2 · 2 citations
Earth and Planetary Sciences · Engineering · Environmental Science · Mathematics · Physics and Astronomy · #Boundary layer #Boundary layer thickness #Couette flow #Cylinder #Flow (mathematics) #Fluid Dynamics and Turbulent Flows #Geometry #Groove (engineering) #Materials science #Mathematics #Mechanics #Meteorological Phenomena and Simulations #Physics #Plant Water Relations and Carbon Dynamics #RADIUS #Reynolds number #Rotational symmetry #Scaling #Taylor number #Taylor–Couette flow #Thermodynamics #Torque #Turbulence #physics.flu-dyn
paper · pdf · doi:10.1017/jfm.2016.179
Accepted by JFM, 27 pages, 23 figures
arxiv created 2016/03/01 · openalex publication_date 2016/04/06 · arxiv updated 2016/05/04 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/05
We present direct numerical simulations of Taylor–Couette flow with grooved walls at a fixed radius ratio \itη=ri/ro=0.714 with inner cylinder Reynolds number up to Rei=3.76× 104 , corresponding to Taylor number up to Ta=2.15× 109 . The grooves are axisymmetric V-shaped obstacles attached to the wall with a tip angle of 90°. Results are compared to the smooth wall case in order to investigate the effects of grooves on Taylor–Couette flow. We focus on the effective scaling laws for the torque, flow structures, and boundary layers. It is found that, when the groove height is smaller than the boundary layer thickness, the torque is the same as that of the smooth wall cases. With increasing Ta , the boundary layer thickness becomes smaller than the groove height. Plumes are ejected from the tips of the grooves and secondary circulations between the latter are formed. This is associated with a sharp increase of the torque, and thus the effective scaling law for the torque versus Ta becomes much steeper. Further increasing Ta does not result in an additional slope increase. Instead, the effective scaling law saturates to the ‘ultimate’ regime effective exponents seen for smooth walls. It is found that even though after saturation the slope is the same as for the smooth wall case, the absolute value of torque is increased, and more so with the larger size of the grooves.