Turbulence characteristics of open channel flow over rough bed

The distribution of velocity and intensity of turbulence are the key hydraulic characteristics of open channel flow. The roughness coefficient is a vital parameter in hydraulic research. Most researches in the past were based on the uniform flow conditions. In the present study, experiments are conducted to investigate the distribution of velocity and intensity of turbulence in a rough bed channel with both uniform flow and non-uniform flow and the results are compared with the researches on the smooth channel. It is found that the velocity can be described by logarithmic profile for uniform flow, but for non-uniform flow, the velocity profile needs to be divided into two regions. The turbulence intensity distribution has the tendency to be more uniform than that of the smooth bed with increasing of relative water depth. In the case of non-uniform flow in open channel with rough bed, the regularities of varying roughness coefficients are similar with that in smooth open channel.