Analysis of Natural Convective Flow of Casson Fluid around an Inclined Rectangular Cylinder

Abstract

This paper presents the natural convection around a tilted hot cylinder immersed in Casson fluid and enclosed by a square container. The parameters of Casson fluid are set to be (0.1≤η ≤ 1.0), aspect ratio (0.1≤AR ≤ 0.7), tilt angle (0^°≤γ ≤ 90^° ) and Rayleigh number (10^3≤Ra ≤ 10^6) are inspected to reveal their influences on Casson fluid flow and heat transfer. The governing equations were solved with COMSOL Multiphysics 5.6 software. The walls of the enclosure and the cylinder are fixed as T_c and T_h. Findings are delineated as stream functions, isothermal contours, and average Nusselt numbers. The study reveals that for the range of η, AR and Ra investigated, the rate of heat transfer of the enclosure wall increases with increasing η, AR and Ra; while for the heated rectangular obstacle, the rate of heat transfer decreases with AR growth but improves with increasing η and Ra. At Ra=106, γ increment results in heat transfer enhancement for the enclosure and cylinder walls. For Ra in the interval of 10^3≤Ra ≤ 10^5, the response of the thermal profiles of both the rectangular cylinder and enclosure walls to cylinder orientation depends on the value of Ra and γ considered.