Flow and heat transfer in the wake region of a semi-circular cylinder embedded within a rectangular channel have been studied experimentally using non-intrusive techniques. The semi-circular cylinder embedded within the channel with a blockage ratio of 0.45 () acts as an obstacle to the incoming fully developed laminar flow and creates a wake region in its downstream side. The velocity field in the downstream wake region is mapped using PIV (particle image velocimetry) technique with water as the working medium. The fluctuating shear layers and the vortices shed by the cylinder interact with the bottom heated wall of the channel. The influence of the wake region of the cylinder manifests on the heat transfer characteristics of the bottom wall of the channel and acts in a way to passively improve the overall heat transfer characteristics. The resulting whole field temperature values are captured using interferometry and augmentation in heat transfer rates vis-à-vis a channel without cylinder are compared. The dominant frequencies of the downstream unsteady flow in the wake of the cylinder are captured using schlieren technique. Heat transfer enhancement up to 42 percentage is observed in the case of the presence of the semi-circular cylinder in the channel in comparison with the flow in a plain channel for the Reynolds number range of 75–200 under which the experiments are performed.

中文翻译：

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嵌入矩形通道内的半圆柱体层流尾流区域的流动和传热测量


使用非侵入式技术对嵌入矩形通道内的半圆柱体尾流区域的流动和传热进行了实验研究。嵌入通道内的半圆柱体阻塞比为 0.45 ()，对进入的完全发展的层流起到障碍作用，并在其下游侧形成尾流区域。以水为工作介质，使用 PIV（粒子图像测速）技术绘制下游尾流区域的速度场。波动剪切层和圆柱体产生的涡流与通道底部加热壁相互作用。气缸尾流区域的影响体现在通道底壁的传热特性上，并以被动改善整体传热特性的方式发挥作用。使用干涉测量法捕获所得的整个场温度值，并与没有圆柱体的通道相比传热率的增强进行比较。使用纹影技术捕获圆柱体尾流下游非定常流的主频率。在雷诺数为 75-200 的范围内进行实验时，与普通通道中的流动相比，通道中存在半圆柱体的情况下，观察到传热增强高达 42%。