Turbulence and dispersion below and above the interface of the internal and the external boundary layers
Turbulence and dispersion below and above the interface of the internal and the external boundary layers
复制标题
内部和外部边界层界面下方和上方的湍流和扩散
DOI：
10.1016/j.jweia.2018.09.021
复制
发表时间：
2018
影响因子：
4.8
通讯作者：
S. Herring
中科院分区：
文献类型：
--
作者：
Vincenzo Sessa;Zheng;S. Herring
本研究着眼于发展的内部边界层（IBL）的块阵列接近急剧变化的表面粗糙度和分散从地面水平源的下游距离的粗糙度长度的比率小于300的影响。这是通过比较一个大涡模拟（LES）与进口-出口周期性边界条件和风洞实验数据的LES与流入边界条件。比较表明，使用流入边界条件导致显着更好的预测正常的雷诺应力，平均浓度和标量方差比使用周期性边界条件。除了既定的方法外，还采用了一种基于垂直雷诺应力的替代方法，以评估在阵列上方形成的边界层的深度，从而能够更清楚地确定界面的位置。据证实，IBL的增长率接近的表面粗糙度的变化可以描述的幂律轮廓，类似于广泛使用的幂律公式的指数为0.8的下游距离的粗糙度长度大于1000的比率。平均浓度和湍流标量通量的分析表明，IBL的存在限制了垂直发展的羽流从地面源，从而导致截留的冠层中的材料。
This study has looked at the development of the internal boundary layer (IBL) over a block array close to a sharp change in surface roughness and its effect on dispersion from a ground level source for ratios of the downstream distance to the roughness length of less than 300. This was done by comparing a Large--Eddy Simulation (LES) with inflow boundary conditions against a LES with inlet--outlet periodic boundary conditions and data from a wind tunnel experiment. The comparison showed that using inflow boundary conditions resulted in significantly better predictions of normal Reynolds stresses, mean concentration and scalar variance than when using periodic boundary conditions. In addition to established methods, an alternative approach based on the vertical Reynolds stress was used to evaluate the depth of the IBL as it developed over the array which enabled the location of the interface to be more clearly defined. It was confirmed that the IBL growth rate close to the change in surface roughness could be described by a power law profile, similar to the widely used power law formula with an exponent 0.8 for a ratio of the downstream distance to the roughness length greater than 1000. An analysis of mean concentration and turbulent scalar fluxes suggested that the presence of the IBL constrained the vertical development of the plume from a ground level source and so led to trapping of material in the canopy layer.
影响因子：
4.3
作者：
Castro, Ian P.;Xie, Zheng-Tong;Coceal, O.
通讯作者：
Coceal, O.
壁粗糙度发生阶跃变化后湍流边界层的发展
影响因子：
3.7
作者：
Hanson R
通讯作者：
Hanson R