| 摘要(英) |
With the unstable changes in the global climate in recent years, natural disasters have been
frequent reports from all over the world. Because of the slope disaster caused by strong wind
and rain, when the soil and rock particles are subjected to internal and external forces, the
violent collapse and flow behavior will also affect the original slope. Erosion and entrainment
of the surface soil and rock on the surface will cause more serious disasters on slopes. It has
caused serious losses to the natural environment and human society in terms of ecology, natural
environment, the economy, and life safety. For this reason, this study observes the flow behavior
of particle collapse using experiments.
This study mainly explores the collapse of the particle bed with different slope gradients
and water flow through experiments and discusses the erosion and deposition phenomena. In
the experiment, an open two-dimensional inclined flume was built, the inclined angle in the
flume was adjusted manually, and the flow discharge of the incoming water was controlled by
PLC, so that the water flow entered the inclined granular bed area. The particles used in the
experiment are 4mm white alumina beads, which are photographed by a high-speed camera and
then processed by image processing to analyze the flow phenomenon of the particles in the flow
tank and use PIV to analyze the velocity field distribution of the fluid flow to observe the solidliquid
two-phase flow. The experimental results mainly analyze the erosive bed and the
depositional bed, respectively, after the particles are affected by the water flow, the erosion area
size, erosion depth, and erosion distance in the eroded bed change with time, and the particles
in the sedimentary bed are entrained by the water flow. The deposition area of the particles
moved to the depositional bed changes with time, and the relationship between the deposition
depth at different trough positions. Through the final erosion area, the distribution situation and
erosion rate under the influence of different inclination angles and flow rates are analyzed, the
relationship between the dimensionless final erosion area and potential energy loss is also
iii
described, and the distribution relationship is fitted with an exponential function.
It can be known from the experimental results that when the water flow rate and the
inclination angle are larger, the erodible particle bed and deposition will be significantly
changed. When the water flow rate is larger, the erosion area and the deposition area are both
positively correlated distributions. This is because the change of water flow will affect the
original frictional resistance between the particles, which will destroy the original structure of
the particles, which will lead to serious erosion and entrainment effects, and then affect the
deposition area distribution in the sedimentary bed. From the erosion distance and the
distribution of erosion depth at different positions in the trough, it is found that when the water
flow and inclination increase, the effect of erosion will become more and more obvious. From
the change of erosion rate and potential energy loss in the particle bed, it is found that the energy
loss will be more severe when the inclination angle is larger. |
| 參考文獻 |
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