Abstract The present paper numerically investigates the laminar, two-dimensional and horizontal flow around a horizontal isothermal rotating cylinder under the buoyancy effect. To study the buoyancy effect, a range of Grashof numbers from 0 to 12 × 104 is used, and to check the effect of the cylinder rotation, the ratio of the rotational speed to the free-stream velocity between −4.5 and 4.5 is applied. The simulation is carried out at the Reynolds number of 200 and the Prandtl number of 0.7. To simulate the fluid flow, the Navier-Stokes equations are numerically solved using a finite-volume scheme. Results show that the interaction of the main stream with the rotation and buoyancy can alter the flow field and heat transfer characteristics such as flow pattern, surface pressure distribution, lift and drag coefficients, and Nusselt number. The clockwise (cw) rotation decreases the amplitude of oscillations in the flow compared to the counterclockwise (ccw) rotation. In ccw rotation, as the Grashof number increases, the mean lift coefficient increases; while in cw rotation, increase in the Grashof number reduces the mean lift coefficient. Moreover, in terms of Grashof numbers ranging between 8 × 104 and 12 × 104, the Nusselt number is almost unchanged.

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热浮力对旋转圆柱流场和传热的影响：数值研究

摘要 本文数值研究了在浮力作用下围绕水平等温旋转圆柱体的层流、二维和水平流动。为了研究浮力效应，使用了从 0 到 12 × 104 的一系列 Grashof 数，并且为了检查圆柱体旋转的影响，应用了转速与自由流速度之比在 -4.5 和 4.5 之间。模拟在雷诺数为 200 和普朗特数为 0.7 时进行。为了模拟流体流动，使用有限体积方案对 Navier-Stokes 方程进行数值求解。结果表明，主流与旋转和浮力的相互作用可以改变流场和传热特性，如流型、表面压力分布、升阻系数和努塞尔数。与逆时针 (ccw) 旋转相比，顺时针 (cw) 旋转会降低流动中的振荡幅度。在逆时针旋转中，随着 Grashof 数的增加，平均升力系数增加；而在顺时针旋转中，格拉肖夫数的增加会降低平均升力系数。而且，对于介于 8 × 104 和 12 × 104 之间的 Grashof 数，努塞尔数几乎没有变化。