Geometric Characteristics of Spur Dike Scour under Clear-Water Scour Conditions

Abstract

Factors such as flow and sediment characteristics affecting the spur dike's local depth of erosion have yielded considerable research results, but there is little discussion of the geometry of the spur dike's local scour holes. This study focuses on the spatial characteristics of the geometry of local scour holes in straight-wall spur dikes. The discussion shows that the spur dike arrangement clearly changes the plane geometry of the scour hole. The maximum scour depth has a power function relationship with the area of the scour hole and the scour hole-volume. Moreover, the ratio of the product of the maximum scour depth and the plane area of the scour hole to the scour hole-volume is a fixed constant. The average slope of upstream of the scour hole and along the axis direction of the spur dike is slightly larger than the angle of repose of the sediment, the slope distribution of the scour holes profiles presents an inverted "U" type, and its profile morphology and slope distribution have geometric similarity. This distribution also reflected that, the interaction between the downward flow and the horseshoe vortex inside the scour hole leads to the formation of a cusp.

The 3-D Morphology Evolution of Spur Dike Scour under Clear-Water Scour Conditions

“…The flow depth and velocity at the upstream of the spur dike are all constant, at h = 0.15 m; U = 0.21 m/s, respectively. The flow intensity U/U c = 0.87, U c is the incipient velocity of sediment [13], which belongs to Clear-Water scour conditions. Before the experiment, the bed of the experimental area is kept flat, and the water was slowly stored in the flume to the design depth, adjusting the speed of the axial flow pump, reaching the design flow strength, and carrying out the scour experiment.…”

“…With the passing of time, the profile morphology of the scour hole remains constant. Zhang et al [13] further reported the slope distribution characteristics of the scour hole profile in the spur dike, and thought that its distribution characteristics were closely related to local flow. Although the above literature [6,12,13] has paid attention to the morphological characteristics of scour hole profiles from the time dimension or the spatial dimension, the relevant discussion on profile area of the scour hole with time evolution has not been mentioned.…”

“…Zhang et al [13] further reported the slope distribution characteristics of the scour hole profile in the spur dike, and thought that its distribution characteristics were closely related to local flow. Although the above literature [6,12,13] has paid attention to the morphological characteristics of scour hole profiles from the time dimension or the spatial dimension, the relevant discussion on profile area of the scour hole with time evolution has not been mentioned. It is important that this parameter is one of the important parameters which cannot be ignored in the local bed shear stress evolution model, namely, the evolution characteristics of the scour hole profile area determines the evolution trend of local bed shear stress [14][15][16][17].…”

A Machine Learning Approach to Evaluating the Damage Level of Tooth-Shape Spur Dikes

“…A three-dimensional (3D) view of the spur dike array can be seen in Figure 6. The weight of each block is 155.16 t, and the volume of each block is 64.65 m 3 . The weight of the core stone ranges from 1 kg to 100 kg, and the thickness of the core stone layer is 3 m. The weight of the armor stone ranges from 200 kg to 300 kg, and the armor stone layer is 4 m high.…”

“…At present, research on channel training structures is mostly focused on the damage mechanism, such as local scour in the vicinity of the structures [1][2][3] and turbulent flow around the structures [4][5][6], and how changes in structure design parameters affect the water flow and sediment transport characteristics [7,8]. Little research about evaluating the damage level of the channel training structures has been carried out so far.…”