Turbulent flow and heat transfer in channels with shark skin surfaces: Entropy generation and its physical significance
Turbulent flow and heat transfer in channels with shark skin surfaces: Entropy generation and its physical significance
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DOI：
10.1016/j.ijheatmasstransfer.2013.10.063
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发表时间：
2014-03-01
影响因子：
5.2
通讯作者：
Herwig, H.
中科院分区：
文献类型：
--
作者：
Jin, Y.;Herwig, H.
为了了解当壁面被鲨鱼皮状纹理覆盖时阻力减小和传热受到影响的机制，确定了局部熵产生率，并与光滑壁面上的流动进行了比较。基于直接数值模拟（DNSs），可以分析靠近壁面的湍流的细节，并得出结论，基本上某些湍流结构被抬离壁面并重新排列，我们称之为抬离和对齐（LOA）的机制。（时间平均）熵产生率的分布支持这种解释，显示出减少旁边的墙壁和增加进一步远离，但是，这样的整体效果导致阻力减少。通过求解热能方程，它表明，也减少了热传递，从而增加了热体保护。(C)2013爱思唯尔有限公司保留所有权利。
In order to understand the mechanisms by which drag is reduced and heat transfer is affected when a wall is covered by a shark skin like texture the local entropy generation rate was determined and compared to that for a flow over smooth walls. Based on direct numerical simulations (DNSs) details of the turbulence close to the wall could be analyzed and lead to the conclusion that basically certain turbulent structures are lifted off the wall and get rearranged, a mechanism we call lift off and alignment (LOA). The distribution of (time mean) entropy generation rates supports this interpretation, showing a reduction next to the wall and an increase further away, however, such that the overall effect leads to a drag reduction. By solving the thermal energy equation it is shown that also heat transfer is reduced thus increasing the thermal body protection. (C) 2013 Elsevier Ltd. All rights reserved.