Dimensionless critical shear stress evaluation from flume experiments using different gravel beds

Friction Angle Measurements on a Naturally Formed Gravel Streambed: Implications for Critical Boundary Shear Stress

We report the first measurements of friction angles for a naturally formed gravel streambed. For a given test grain size placed on a bed surface, friction angles varied from 10" to over 100'; friction angle distributions can be expressed as a function of test grain size, median bed grain size, and bed sorting parameter. Friction angles decrease with increasing grain size relative to the median ...

Analysis of Gravel River Beds using Three-Dimensional Laser Scanning

The size and shape of the stones in dry gravel river beds are of interest in geology and river hydraulics. The topography of a bed surface can be measured by three-dimensional laser scanning. A method is described for fitting ellipsoids to the surfaces of individual stones to estimate their size, shape and orientation in the river bed. Different cost functions are evaluated and the methods are ...

Exploring accuracy of statistical characterization of gravel beds using Kinect device in the laboratory scale

Mountainous river beds-generally consist of gravel particles that the precise description of such bed is not only important hydraulically, but also it has great environmental significance. The accurate estimation of bed roughness gives us valuable information to make reliable hydraulic models of flow in river with rigorous bed form. This study discuses about the accuracy of the Kinect device in...

Effect of soil composition on critical water erosion shear stress

Computer Vision for Wave Flume Experiments

During the past several decades, a number of attempts have been made to contain oil slicks (or any surface contaminants) in the open sea by means of a floating barrier. Many of those attempts were not very successful especially in the presence of waves and currents. The relative capabilities of these booms have not been properly quantified for lack of standard analysis or testing procedure (Hud...