粗糙床面坡面流流场及紊动特性试验研究  

Experimental study of velocity distribution and turbulence characteristics of overland flow over rough bed

作　　者：季铭昱 程年生 JI Ming-yu;CHENG Nian-sheng(Ocean College,Zhejiang University,Zhoushan 316021,China)

机构地区：[1]浙江大学海洋学院,浙江舟山316021

出　　处：《泥沙研究》2024年第2期41-47,共7页Journal of Sediment Research

基　　金：国家自然科学基金项目(51979242)。

摘　　要：应用粒子图像测速技术对水深为5~8 mm的粗糙床面坡面流流场进行了详细观测,对试验资料进行了时间-空间双平均处理,结果表明:在低淹没度的床面糙率影响下,坡面流流速分布基本符合对数-尾流规律,其中卡门常数与普通明渠流一致,但尾流函数常数明显偏小;相较于光滑床面,粗糙元增强了水流流向的紊动强度,同时致使紊动强度在水深范围内的分布更趋均匀;水流切应力分布以雷诺切应力为主导,粗糙元引起的形状切应力可以忽略不计;水流的空间波动主要存在于床面附近,但流速的空间波动强度与紊动强度相比普遍偏小。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 Karman 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.

关 键 词：坡面流 粗糙床面 流速分布 紊动特性 PIV 时间-空间双平均 

分 类 号：TV131[水利工程—水力学及河流动力学]