SPATIAL CORRELATION STRUCTURES OF WATER SURFACE FLUCTUATION AND TURBULENCE IN OPEN-CHANNEL FLOWS
SPATIAL CORRELATION STRUCTURES OF WATER SURFACE FLUCTUATION AND TURBULENCE IN OPEN-CHANNEL FLOWS
复制标题
明渠水流水面涨落和湍流的空间相关结构
DOI：
10.2208/prohe.47.439
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
K. Shimoyama
中科院分区：
文献类型：
--
作者：
H. Miyamoto;K. Shimoyama
本文研究了明渠水流中水面脉动与紊流结构的关系。这里检查的瞬时速度矢量和相应的水面线测量的同时图像测量技术。首先，适当的正交分解（POD）的水面波动成功地提取其主要的空间特征表示为正弦波的形状。然后，利用POD特征向量的模态幅值，计算了幅值与速度脉动之间的空间相关系数。结果表明，水面附近存在一个薄的表面层，其中速度脉动似乎与表面平行，水面脉动与具有相同纵向尺度的大尺度湍流结构之间存在着很强的联系。
In this paper, we investigate relations between water surface fluctuations and turbulence structures in openchannel flows. Examined here are instantaneous velocity vectors and corresponding water surface profiles measured by a simultaneous image measurement technique. At first, the proper orthogonal decomposition (POD) of the water surface fluctuations successfully extracts their predominant spatial characteristics that are represented as sinusoidal wave shapes. Then, by using the modal amplitudes of the POD eigenvectors, we calculate spatial correlation coefficients between the amplitudes and the velocity fluctuations. The result shows that there exists a thin surface layer near the water surface in which velocity fluctuations seem to be parallel to the surface and that there are strong relationships between the water surface fluctuations and the large scale turbulent structures that have the same longitudinal scale.