Author(s): Dong Zengnan; Wang Jinjun; Chen Changzhi; Xia Zhenhuan
Linked Author(s):
Keywords: Open channel flow; Turbulence; Rough bed
Abstract: The temporal mean velocity and velocity fluctuations in uniform, rough open channel turbulent flows were measured in full detail and a large amount of information about the wall region near the bed was obtained using a laboratory-developed Laser Doppler Anemometer (LDA) of very fine space resolution and high noise-reduction capability. The influence of boundary roughness on flow characteristics was examined by changing the relative smoothness scale, H/k_s of the flow. It is proposed that there are three sorts of bed roughness, namely the large scale roughness (H_T/k_s 5). The small scale roughness is of more universal significance to engineering practice, and much attention is devoted to the characteristics of flow over boundaries of such roughness. The results offer a basis for mathematical modelling of open channel turbulent flows.
Year: 1991