| Slope flow resistance is the core problem to study the characteristics of slope water flow. It is an important parameter which is an indispensable parameter in slope flow and confluence simulation. It is also important to control slope erosion and soil and water conservation. Plants are an important factor affecting the flow resistance of the slope. There are many types and growth states in the flowing water.These plants can change the flow structure, increase the kinetic energy loss, slow the flow rate of the water flow and have a great influence on the slope water flow resistance, so the role of plants on slope water flow resistance is to explore the basis of slope hydrodynamic laws. Because of the complex and changeable characteristics of vegetation flow, it is difficult to analyze the concrete influence of vegetation cover on slope resistance. Therefore, it is very important to study the effect of plant on the flow resistance coefficient of slope flow. At present, the experimental study shows that the qualitative results or empirical formulas are only obtained by studying the changes of the characteristics of plant water flow, and only some qualitative results or empirical formulas are obtained. It is necessary to further study the mechanism of plant action on water flow, so that it can be universally applied the law. In this paper, the effects of different deflection angles and leaf area on the flow resistance characteristics of the three slopes (0.00%,0.50%, 1.00%) were simulated by changing the water depth under the condition of varying water depth.Reynolds number, energy loss along the process and the change of water flow resistance coefficient with average water depth and test slope, and then reveal the mechanism of plant deflection angle and leaf area change on water flow characteristics.The main conclusions are as follows:①Plant in the role of water under the deflection, can increase the flow of viscous force, reduce the inertia of water flow, so that the flow structure is more stable, reduce the energy loss and resistance of water. The plant deflection angle has little effect on the Reynolds number, and the energy loss and the Darcy-Weisbach coefficient decrease with the plant deflection angle. The formula of Darcy-Weisbach coefficient with plant deflection angle is established and the formula is carried out with the measured data.It is found that the formula has good applicability to simulate the flow resistance coefficient under different deflection angle conditions.②Plant leaves are the main source of water resistance, the increase of plant leaf area increases the viscous force of the flow, the inertia force decreases and the turbulent state of the flow decreases. The Reynolds number decreases with the increase of plant leaf area, and the energy loss and the Darcy-Weisbach coefficient increase with the increase of plant leaf area, and with the increase of leaf area,the energy loss and the flow resistance coefficient increase And the Darcy-Weisbach coefficient formula for plant leaf area is established. The formula is also applicable to the calculation of Darcy-Weisbach coefficient under different leaf area of plant. |
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