Asymptotic analysis of the near-wall region of turbulent natural convection flows
Asymptotic analysis of the near-wall region of turbulent natural convection flows
复制标题
湍流自然对流近壁区域的渐近分析
DOI：
--
复制
发表时间：
2005
影响因子：
3.7
通讯作者：
H. Herwig
中科院分区：
文献类型：
--
作者：
M. Hölling;H. Herwig
本文对竖直壁面附近有换热的高格拉肖夫数湍流自然对流进行了渐近分析。近壁边界层有一个受粘性影响的内层和一个完全湍流的外层，类似于强制对流边界层的结构。标度律和壁函数的渐近匹配的重叠层中的温度梯度。温度壁函数则是一个简单的对数函数的壁距离，而在重叠层的速度分布是一个更复杂的相关。这些壁函数中的常数是从高质量的数据推导出的大Grashof数。实验以及数值剖面作为一个整体是非常好地再现壁函数和粘性子层剖面的组合。因此，这些新的渐近剖面可以用于CFD代码，以避免非常精细的网格靠近墙壁，当格拉肖夫数高。
High-Grashof-number turbulent natural convection in the vicinity of vertical walls with heat transfer is analysed asymptotically. The near-wall boundary layer has a viscosity-influenced inner layer and a fully turbulent outer layer, similar to the structure of forced convection boundary layers. Scaling laws and wall functions are found by asymptotic matching of the temperature gradients in the overlap layer. The temperature wall function then is a simple logarithmic function of wall distance whereas the velocity profile in the overlap layer is a more complex correlation. Constants in these wall functions are deduced from high-quality data for large Grashof numbers. Experimental as well as numerical profiles as a whole are very well reproduced by the combination of wall functions and viscous sublayer profiles. Therefore these new asymptotic profiles can be used in CFD codes to avoid very fine grids close to the wall, when Grashof numbers are high.