【作者】 张全清；

【导师】 文恒；

【作者基本信息】 内蒙古农业大学 ， 农业水土工程， 2008， 硕士

【摘要】 平原灌区水闸闸下冲刷破坏严重且普遍存在。冲刷破坏位置绝大多数发生在消力池下游海漫及防冲槽处。冲刷破坏原因很多,当消力池设计合理,闸下出流消能充分的情况下,海漫末端仍会产生冲坑,其产生的原因除还有剩余的动能外,主要是由于断面流速未恢复常态,近底流速偏大所致。本文在对海漫加糙已有研究的基础上,对不同个轮胎糙体组合后的断面流速分布规律进行了细化试验,原来试验是在加糙体后20cm处近底流速只测一点,现增加为35点,选定了20cm、25cm、30cm、35cm四种水位工况,加糙体分别布设一至七排,量测加糙体后垂直水流方向的平面上各观察点的流速值,进行加糙机理的分析,得到随着水位和糙体排数的增加,距槽底7.5cm以下部分的流速相对减小,距槽底7.5cm以上的轮胎面上部周围形成一个相对大的流束带,水位为25cm以上时,轮胎孔中心正对的测点C4点的流速不再比上一层B4点的流速大。在糙体增加到七排时,1、3点的流速线也由有折点的线变成一条相对平滑的曲线。通过对近底流速在水位、糙体排数、断面位置的影响下进行了曲线拟合,得到了近底流速的拟合公式。分析了在不同水位不同糙体布置下断面上各点的流速变化情况,和不同水位下同糙体排数同一点处流速变化情况。由于试验条件及时间所限,所得结论还需实际工程试验验证。更多还原

【Abstract】 Under the plain irrigation area dam floodgate washes out the destruction to be serious also the universal existence. Washing out destroys the position overwhelming majority to occur in the toe basin downriver sea inundates and guards against flushes the trough place. The reasons of washing out the destruction are very many, when the toe basin design is reasonable, under the floodgate the class disappears can in the full situation, the sea inundated the terminal still to be able to produce flushes the pit, it produced the reason besides also had the kinetic energy which surplus should disappear, mainly was because the cross section speed of flow has not restored the habit, the near bottom speed of flow was the result of greatly.This article in inundates to the sea adds roughness had the research in the foundation, and had a detailed test on the distribution of speed of flow of section behind each different tyre roughness which is combined, plus the original in the behind of the roughness of the nearly 20cm next to the end of it, is measured only one point. Now increasing by 35 points, and selecting 20cm, 25cm, 30cm and 35cm, which is four kinds of water lever working conditions. The roughness is set up from one till seven rows respectively, measuring the speed of flow the observation point in the direction of water flow, behind the roughness and vertical cross section, and carrying out the analysis adding roughness mechanism. With the water lever and rows of roughness increasing, now the speed of flow at the bottom part of the channel under 7.5cm is smaller relatively, but at the bottom of type above 7.5cm, formulated a relatively large flow banding. The tyre is the central of the hole measuring point C4, which is bigger than upper that of B4, when the number of row of roughness reaches 7 rows, the line of the speed of flow is changed from a broken line into a relatively smooth curve one, under the influence of the water level, the rows of roughness of the location of section, and the speed of flow near the bottom are being simulated, and reaches the simulated formula finally.Analysis the changes in the speed of flow of the respective point above the section under the different water level, and different roughness body of arrangement form , and analysis the changes of the same one point of the rows of the same roughness body under the different water level. Because the condition of test and time are limited, the gained conclusion needs rectifying under the actual project further.更多还原