Experimental study of velocity distribution and turbulence characteristics of overland flow over rough bed
Particle image velocimetry(PIV)technique was applied to conduct detailed measurements of over-land flow under the rough bed condition,with flow depth varying in the range of 5～8 mm.The experimental data were processed and analyzed by temporal-spatial(double)averaging.The results show that the velocity distribution of the overland flow primarily follows the logarithmic-wake law,in which the von Kármán constant is the same as that of ordinary open channel flow,but the wake function constant is significantly smaller.Com-pared to the smooth-bed overland flow,roughness elements enhance the turbulence intensity in the flow direc-tion,making the turbulence intensity more uniform within the entire flow depth.The distribution of the shear stress is dominated by the Reynolds shear stress.The spatial variation in flow mainly exists near the bed,yet it is considerably lower than the turbulence intensity.
万方数据
维普
