Coriolis force effects on radial convection in a cylindrical annulus. (15th June 2022)

• Record Type: Journal Article
• Authors: Pitz, Diogo B.; Wolf, William R.
• Is Part Of: International journal of heat and mass transfer. Volume 189(2022)
• Publication Date: 2022-06-15
• Subjects: Buoyancy-driven flows -- Rotating convection -- Rotating cavities -- Direct numerical simulation; 0000 -- 1111; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2022.122650
• Languages: English
• ISSNs: 0017-9310

Abstract

Abstract : The effect of rotation on radial convection in a cylindrical annulus is studied using DNS. Rotation stabilizes the flow and favours the formation of large-scale convection cells. Small-scale structures dominate in the cases without rotation. Rotation affects the turbulent kinetic energy distribution in the radial direction. Reynolds stress anisotropy maps are used to quantify the stabilizing effect of rotation. Graphical abstract: Abstract: Thermal convection under the influence of rotation appears in a wide range of engineering and geophysical applications, and has been investigated extensively both experimentally and numerically utilizing different canonical configurations. The problem of radial convection in a cylindrical annulus, studied in the present work, has received less attention than other configurations, such as rotating Rayleigh-Bénard convection. It has long been known that rotation has a stabilizing effect and, in the limit of strong rotation, a two-dimensional flow emerges, resulting in reduced heat transfer rates. Here, direct numerical simulations are performed for buoyancy-driven flows in a cylindrical annulus bounded by two parallel disks with and without rotation. By maintaining a radial gravity term analogous to a centrifugal acceleration even in the stationary cases, it is possible to isolate the effect of the Coriolis force on the flow. As expected, when rotation is imposed the flow is characterized by large-scale structures and the heat transfer rates are significantly reduced. Turbulence statistics are presented for the mean temperature profiles, temperature and velocity fluctuations, turbulent kinetic energy budgets, and Reynolds stress anisotropy tensor. It is shown that rotation significantly affects the distribution of turbulent kinetic energy throughout the radial direction, in particular away from the cylindrical surfaces. The anisotropy maps reveal that the turbulence is quasi-two-dimensional in the rotating cases, even for the highest value of R a considered, whereas without rotation the core region approaches the isotropic limit with increasing R a .