利用粒子图像测速，本征正交分解和速度相关表征高粗糙度表面流动结构

2019/07/19   下载量： 0 次

方案摘要

方案下载
应用领域 能源/新能源
检测样本 其他
检测项目
参考标准 暂无

采用LaVision公司由DaVis软件平台和ImagerPro型相机构成的粒子成像测速系统，对于水洞中的含有粗糙表面的流体的流场进行了测量并利用本征正交分解等数学工聚，对流动结构和水洞壁面表面粗糙度的相关性进行了实验研究。

方案下载
配置单
方案详情

      High Reynolds number flow inside a channel of rectangular cross section is examined using Particle Image Velocimetry. One wall of the channel has been replaced with a surface of a roughness representative to that of real hydropower tunnels, i.e. a random terrain with roughness dimensions typically in the range of ≈10% - 20% of the channels hydraulic radius. The rest of the channel walls can be considered smooth. The rough surface was captured
from an existing blasted rock tunnel using high resolution laser scanning and scaled to 1:10. For quantification of the size of the largest flow structures, integral length scales are derived from the auto-correlation functions of the temporally averaged velocity. Additionally, Proper Orthogonal Decomposition (POD) and higher-order statistics are applied to the instantaneous snapshots of the velocity fluctuations. The results show a high spatial heterogeneity of the velocity and other flow characteristics in vicinity of the rough surface, putting outer similarity treatment into jeopardy. Roughness effects are not confined to the vicinity of the rough surface but can be seen in the outer flow throughout the channel, indicating a different behavior than postulated by Townsend’s similarity hypothesis. The effects on the flow structures vary depending on the shape and size of the roughness elements leading to a high
spatial dependence of the flow above the rough surface. Hence, any spatial averaging,
e.g. assuming a characteristic sand grain roughness factor, for determining local flow parameters becomes less applicable in this case.

上一篇 在一个双稳湍流涡旋火焰中，对间歇性动态的时间-频率定位
下一篇 将甲苯LIF应用于跨音速喷嘴流动以识别不完全分子混合区域

文献贡献者

北京欧兰科技发展有限公司
金牌会员 丨 第17年
查看全部资料
相关仪器 更多
相关方案
更多

相关产品

当前位置： 欧兰科技 方案 利用粒子图像测速，本征正交分解和速度相关表征高粗糙度表面流动结构

关注

拨打电话

留言咨询