Effect of Prandtl number and rotation on vortex shedding behind a circular cylinder subjected to cross buoyancy at subcritical Reynolds number |
| |
Affiliation: | 1. Mechanical Engineering, R. V. R & J. C College of Engineering (A), Guntur 522019, India;2. Mechanical Engineering, V. R. Siddhartha Engineering College (A), Kanuru 520007, India;1. School of Electrical and Automation Engineering, Hefei University of Technology, Hefei, 230009, PR China;2. Engineering Technology Research Center of Industrial Automation, Anhui Province, Hefei, 230009, PR China;1. Department of Mechanical Engineering, Jadavpur University, Kolkata 700032, India;2. Department of Power Engineering, Jadavpur University, Salt Lake, Kolkata 700106, India;1. Department of Physics, Xiamen University, 422 Siming South Road, Xiamen 361005, China;2. Institute for Complex Adaptive Matter, University of California, Davis, CA 95616, USA |
| |
Abstract: | We perform a two-dimensional numerical simulation following a finite volume approach to understand the vortex shedding (VS) phenomena around a circular cylinder subjected to cross thermal buoyancy at a subcritical Reynolds number, Re = 40. The flow is considered in an unbounded medium. The cylinder may either be stationary or rotating about its centroidal axis. At the subcritical Reynolds number, the flow and thermal fields are steady without the superimposed thermal buoyancy (i.e. for pure forced flow). However, as the buoyancy parameter (Richardson number, Ri) increases, flow becomes unstable, and eventually, at some critical value of Ri, periodic VS is observed to characterize the flow and thermal fields. An extended Stuart–Landau model is used in this work for the accurate quantitative estimation of the critical Richardson number for the onset of VS. The above phenomena of VS with imposed buoyancy is strongly dependent on the type of the fluid being used. We quantify here the minimum heating requirement for the initiation of VS by choosing three different types of fluids having Prandtl numbers, Pr = 0.71, 7, and 100. The dimensionless rotational speed (Ω) ranges between 0 and 4. It is revealed that as Pr increases, heating requirement also increases for the initiation of VS. A possible explanation for the observation is provided. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|