The Riverbed Evolution In Lanzhou Section Of The Yellow River And The Analysis Of Numerical Simulation

This paper mainly includes two aspects of content. In the first part, analyzed the river channel evolution of the Yellow River in lanzhou section, In the second department, 90 degrees horizontal intake numerical model is established, and analyzed the characteristics of the flow and the cross section at the entrance of the water inlet near the waters.Up is particularly important in lanzhou section of the Yellow River to the influence of the reservoir, the reservoir is the liujiaxia reservoir and results of this paper analyses the influence, in 1986, after two joint operation is bounded, 54 years from 1956 to 1956 years of history, the first paragraph belongs to the natural state,state of the second paragraph belongs to joint Long Liu reservoir scheduling, the hydrological data, sediment data of the Yellow River in lanzhou section of the key analysis, thus it is concluded that the influence of reservoir built on the river and river bed evolution in lanzhou.In the second part, mainly research the influence of the construction of the hydrological characteristics of river channel.In order to study the water inlet near the sensitive waters flow changes, including amplitude range, the using water intake model of Angle of 90 degrees to study, using the method of numerical simulation,using the former processor ICEM modeling and FLUENT12.0 commercial software to calculate, reuse tecplot software for numerical analysis, select the RSM Reynolds stress model.According to the characteristics of the actual boundary conditions of water engineering, velocity retio as the main parameter, three-dimensional hydraulic characteristics of the intake area near the sensitive waters.By establishing the mathematical model, the analysis of the results, it is concluded that near the water inlet,the hydraulic characteristics is:(1) near the water inlet,the velocity distribution in intake upstream shore side is slants big, in the downstream near the underlying presence at the entrance of the low velocity zone;(2)the main channel to flow in the intake upstream deflect a certain distance, department of water into the sink, the rest continue to flow to the downstream of the main channel;(3) under the condition of the same velocity ratio, with the increase of the depth of the water, the main channel to flow direction of the velocity decreases, but the direction of water flow rate has a tendency to increase.The section at the entrance,the hydraulic characteristics of the performance for(1) with the increase of velocity ratio, the cross section at the entrance, the velocity peak is falling, the minimum value is increasing;(2) no matter how much the velocity ratio is, the entrance at the bottom of the upper has a low speed, when the velocity ratiois larger, the area that even have a reflux;(3) when the velocity ratio is not same, the entrance section near the bottom there is a low speed area, here are slowly or stagnation.