DNS of turbulent channel flows with two- and three-dimensional roughness
DNS of turbulent channel flows with two- and three-dimensional roughness
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DOI：
10.1080/14685240600827526
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发表时间：
2006-01
影响因子：
1.9
通讯作者：
P. Orlandi;S. Leonardi
中科院分区：
文献类型：
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作者：
P. Orlandi;S. Leonardi
DNS结果与二维和三维粗糙元的湍流槽道流进行了讨论。重点是连续粗糙度元素之间的间隔很小的表面。在这些情况下，粗糙度函数受到粗糙度元素的形状的强烈影响。通常，粗糙度函数是针对几何参数绘制的，并且不会出现令人满意的相关性。或者，当粗糙度函数相对于波峰平面上的法向速度的均方根作图时，可以实现相当好的数据崩溃。这种良好的关系先前在二维几何扰动中观察到（Orlandi，P.，Leonardi，S.和Antonia，R.一、2006年，在一个壁上具有横向或纵向粗糙元件的湍流通道流。Journal of Fluid Mechanics，to appear），在这里它被扩展到在实际应用中更常见的三维几何形状。三维粗糙度比二维粗糙度对上覆水流的影响更大。这是通过瞬时速度和涡量的可视化，并通过湍流强度和雷诺剪应力分布之间的比较。
DNS results for turbulent channel flow with two- and three-dimensional roughness elements are discussed. The focus is on surfaces where the separation between consecutive roughness elements is small. In these cases, the roughness function is strongly influenced by the shape of the roughness elements. Usually, the roughness function is plotted against geometrical parameters and a satisfactory correlation does not emerge. Alternatively, a rather good collapse of the data is achieved when the roughness function is plotted against the rms of the normal velocity on the plane of the crests. This good relationship was observed previously for two-dimensional geometrical disturbances (Orlandi, P., Leonardi, S. and Antonia, R. A., 2006, Turbulent channel flow with either transverse or longitudinal roughness elements on one wall. Journal of Fluid Mechanics, to appear), here it is extended to three-dimensional geometries that are more often found in practical applications. Three-dimensional roughness has a strong influence on the overlying flow than two-dimensional roughness. This is shown through visualizations of the instantaneous velocity and vorticity, and through the comparison among the turbulent intensities and Reynolds shear stress distributions.