Abstract Surface structuring in form of streamwise-aligned triangular ridges is investigated in the framework of a fully developed turbulent channel flow with constant wall temperatures of different values prescribed on the upper and lower walls at Re b = 18000 . Two arrangements of the ridges on both channel walls are considered – a symmetrical arrangement and a staggered arrangement with a spanwise shift of the upper wall structure by a half ridge separation. The ridges generate a strong large-scale secondary motion and hence enhance momentum and heat transfer in the channel by approximately 30% relatively to the smooth channel. In spite of the fact that both arrangements translate into very similar global flow properties, the composition of skin friction coefficient and Stanton number significantly differs. The componental split-up of the friction coefficient reveals that the enhancement of momentum transfer mainly originates from the dispersive component linked to the secondary flows. For the Stanton number, however, the enhancement arises not only from the dispersive component, but also from a strong modification of the turbulent flow properties.

中文翻译：

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流动脊上湍流中的二次流动和传热

摘要 在完全发展的湍流通道流动的框架内研究了呈流向排列的三角形脊形式的表面结构，在 Re b = 18000 时，在上壁和下壁上规定了不同值的恒定壁温。考虑了两个通道壁上的脊的两种排列 - 对称排列和交错排列，上壁结构通过半脊分离在翼展方向上移动。脊产生强烈的大规模二次运动，因此相对于光滑的通道，通道中的动量和热传递增加了大约 30%。尽管两种排列都转化为非常相似的整体流动特性，但皮肤摩擦系数和斯坦顿数的组成却有很大不同。摩擦系数的分量分解表明，动量传递的增强主要源于与二次流相关的弥散分量。然而，对于斯坦顿数，增强不仅来自色散分量，还来自湍流特性的强烈修改。