A NEW MEASURE FOR DIRECT MEASUREMENT OF THE BED SHEAR STRESS OF WAVE BOUNDARY LAYER IN WAVE FLUME  

作　　者：HUO Guang WANG Yi-gang YIN Bao-shu YOU Zai-jin 

机构地区：[1]Key Laboratory of Coastal Disaster and Defense, Ministry of Education, Hohai University, Nanjin 210098,China [2]Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China [3]State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China [4]Coastal Unit., Department of Natural Resources, Dangar NSW, Australia

出　　处：《Journal of Hydrodynamics》2007年第4期517-524,共8页水动力学研究与进展B辑（英文版）

基　　金：National Natural Science Foundation for Distinguished Young Scholars of China (Grant No. 40428001).

摘　　要：In this article, a shear plate was mounted on the bottom in a wave flume and direct measurements of the smooth and rough bed shear stress under regular and irregular waves were conducted with the horizontal force exerted on the shear plates by the bottom shear stress in the wave boundary layer. Under immobile bed condition, grains of sand were glued uniformly and tightly onto the shear plate, being prevented from motion with the fluid flow and generation of sand ripples. The distribution of the bottom mean shear stress varying with time was measured by examining the interaction between the shear plate and shear transducers. The relation between the force measured by the shear transducers and its voltage is a linear one. Simultaneous measurements of the bottom velocity were carried out by an Acoustic Doppler Velocimeter （ADV）, while the whole process was completely controlled by computers, bottom shear stress and velocity were synchronously measured. Based on the experimental results, it can be concluded that （1） the friction coefficient groews considerably with the increase of the Reynolds number, （2） the shear stress is a function varying with time and linearly proportional to the velocity. Compared with theoretical results and previous experimental data, it is shown that the experimental method is feasible and effective, A further study on the bed shear stress under regular or irregular waves can be carried out. And applicability to the laboratory studies on the initiation of sediments and the measurement of the shear stress after sediment imigration.In this article, a shear plate was mounted on the bottom in a wave flume and direct measurements of the smooth and rough bed shear stress under regular and irregular waves were conducted with the horizontal force exerted on the shear plates by the bottom shear stress in the wave boundary layer. Under immobile bed condition, grains of sand were glued uniformly and tightly onto the shear plate, being prevented from motion with the fluid flow and generation of sand ripples. The distribution of the bottom mean shear stress varying with time was measured by examining the interaction between the shear plate and shear transducers. The relation between the force measured by the shear transducers and its voltage is a linear one. Simultaneous measurements of the bottom velocity were carried out by an Acoustic Doppler Velocimeter （ADV）, while the whole process was completely controlled by computers, bottom shear stress and velocity were synchronously measured. Based on the experimental results, it can be concluded that （1） the friction coefficient groews considerably with the increase of the Reynolds number, （2） the shear stress is a function varying with time and linearly proportional to the velocity. Compared with theoretical results and previous experimental data, it is shown that the experimental method is feasible and effective, A further study on the bed shear stress under regular or irregular waves can be carried out. And applicability to the laboratory studies on the initiation of sediments and the measurement of the shear stress after sediment imigration.

关 键 词：wave boundary layer friction coefficient shear plate shear stress Acoustic Doppler Velocimeter （ADV） 

分 类 号：TV131[水利工程—水力学及河流动力学]