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首页> 外文期刊>International Journal of Heat and Fluid Flow >Analysis of turbulent flow in channels roughened by two-dimensional ribs and three-dimensional blocks. Part Ⅰ: Resistance
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Analysis of turbulent flow in channels roughened by two-dimensional ribs and three-dimensional blocks. Part Ⅰ: Resistance

机译：分析由二维肋和三维块粗糙化的通道中的湍流。第一部分：抵抗

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The characteristics of a turbulent flow in channels with two-dimensional ribs and three-dimensional blocks are investigated in the context of surface roughness effects. Reynolds-averaged Navier-Stokes equations, coupled with the k-w turbulence model with near-wall treatment, are solved by a finite-volume method. Calculations are carried out for ribs with square, triangular, semicircular and wavy cross-sections over a range of rib spacing (pitch) and Reynolds numbers. The pitch that yields maximum resistance is identified for each roughness. For all cases, the space-averaged velocity profile exhibits a logarithmic region, with a roughness function that varies logarithmically with the roughness Reynolds number. The roughness function depends on the rib shape and pitch ratio but is independent of the absolute rib size. Analysis with three-dimensional blocks reveals similar but more complex behavior. A logarithmic region exists in the velocity profile but with much smaller block heights compared to ribs. The different block arrangements exhibit quite distinct flow characteristics but the differences tend to vanish as the block height decreases. In general, a Reynolds-averaged numerical model successfully describes the principal features of wall roughness that have hitherto fore been the purview of experimental correlations. Part Ⅱ of the paper extends the model to study heat transfer from a rough surface.
机译：在表面粗糙度影响的背景下，研究了具有二维肋和三维块的通道中湍流的特性。用有限体积法求解雷诺平均的Navier-Stokes方程，并结合采用近壁处理的k-w湍流模型。在具有一定范围的肋骨间距（螺距）和雷诺数的情况下，对具有方形，三角形，半圆形和波浪形横截面的肋骨进行计算。对于每个粗糙度，确定产生最大电阻的螺距。对于所有情况，空间平均速度分布都显示一个对数区域，其粗糙度函数随粗糙度雷诺数对数变化。粗糙度函数取决于肋的形状和螺距比，但与绝对的肋尺寸无关。使用三维块进行的分析揭示了相似但更复杂的行为。速度分布图中存在对数区域，但与肋骨相比，块高低得多。不同的块体布置表现出截然不同的流动特性，但是随着块体高度的减小，差异趋于消失。通常，雷诺平均数值模型成功地描述了迄今为止壁厚的主要特征，而这些主要特征一直是实验相关性的研究范围。本文的第二部分扩展了模型，以研究从粗糙表面传热。

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