丁坝挑角对曲线交汇口弯道的影响

发布时间：2018-07-28 11:50

【摘要】：天然河道中，支流斜接干流河道是广泛存在的自然现象。因为天然河道形态不一，根据交汇口附近干流河道的形态特点，可分为曲线型交汇与直线型交汇两大类型。曲线型河道水流流态本身就十分复杂，支流的交汇使得曲线交汇口局部几何形态及水力条件更为复杂。因此，曲线型交汇口弯道水流特性研究不仅具有重要的理论价值，而且在航运、水工建筑物设计、河道整治等方面具有积极的实用价值。本课题以曲线型交汇口弯道的防护为出发点，研究不同挑角的丁坝群对曲线型交汇口弯道的影响。当前，丁坝是河道整治工程中一种十分常见的建筑物，具有束水攻沙、控制河势、壅高水位及保护岸滩等多种作用。特别是对护岸工程来说，修建丁坝后，水流受到压缩，使丁坝下的断面突然放大，水流由于分离而形成了狭长的回流区。所以，，对于研究丁坝群挑角对曲线型交汇口弯道的影响具有普遍的实践意义。目前有关于丁坝水流的研究大多数是针对直段河道而布置的丁坝，而在实际河道中，大多数设计是针对丁坝在弯道上的险工。本课题以曲线型交汇口弯道中布置的丁坝群为研究对象，针对曲线型交汇口弯道水流特性，采用“水流跟踪者”先进的三维声学多普勒流速仪ADV(Aeoustic Doppler Veloimeter)对曲线型交汇口弯道及丁坝附近的水流流速进行系统的测量，获取了有关曲线型交汇口弯道和丁坝的信息，从多方面研究不同挑角的丁坝群对曲线型交汇口弯道的影响。本试验采用平底有机玻璃水槽进行概化模型试验，主要分析了非淹没丁坝群的挑角在不同水位以及不同交汇角下对曲线型交汇口弯道防护的作用，不同挑角丁坝群对曲线型交汇口弯道自由水面形态、纵向流速分布、纵向脉动强度分布的影响，同时也探讨了水位变化对丁坝水流流态的影响。研究得出：在曲线型交汇口弯道凹岸布置丁坝群后，可以束窄水流，调整、优化流速分布，改变弯道水流的自由水面形态。在交汇角和水位一定的情况下，改变丁坝挑角对曲线型交汇口弯道的流速影响产生一定的影响；在交汇角和丁坝挑角一定的情况下，水位对丁坝附近水面形态影响相对较小，但是对弯道凸岸影响相对较大。本课题针对不同挑角丁坝群对曲线型交汇口弯道水力特性进行较深入系统的分析，旨在为这类交汇口弯道的进一步科学研究、工程设计、河道整治及其它特性研究提供参考。
[Abstract]:In natural river, the branch stream channel is a widespread natural phenomenon. Because the natural channel is different, it can be divided into two types according to the morphological characteristics of the main stream channel near the intersection. The flow pattern of the curved channel is very complicated itself, and the intersection of the tributaries makes the curve intersection part. The geometric shape and hydraulic conditions are more complex. Therefore, it is of great theoretical value to study the flow characteristics of curved intersection curve, but also has positive practical value in shipping, hydraulic structure design, river regulation and so on.
This subject takes the protection of curved intersection curve as the starting point to study the influence of dike groups with different pick angles on the curve of curved intersection. At present, the dike is a very common building in the river regulation project, which has many functions, such as water attack, control of the river, the water level of the river and the bank, and so on. Especially for the bank protection project, After the construction of a spur dike, the flow is compressed, which makes the cross section of the dike suddenly magnified, and the flow of water has formed a narrow reflux area due to separation. Therefore, it is of general practical significance to study the influence of the pick angle of the dike group on the curve of the curve intersection.
At present, most of the research on the flow of spur dikes is the spur dike arranged for the straight channel. In the actual River, most of the design is aimed at the dangerous work of the spur dam on the bend. This subject takes Ding Baqun as the research object in the curve intersection curve. The advanced three-dimensional acoustic Doppler flow meter ADV (Aeoustic Doppler Veloimeter) is used to measure the flow velocity near the curved intersection curve and the dike near the spur dike. The information about the curve and spur dike at the curve intersection is obtained, and the influence of the dike groups with different pick angles on the curve of the curve intersection is studied in many ways. The effect of the angle of the non submerged spur group at different water level and different intersection angle to the curve intersection curve protection is mainly analyzed by using the flat bottom organic glass tank. The influence of the different pick dike groups on the free surface shape, the longitudinal velocity distribution and the longitudinal pulsation intensity distribution in the curve intersection curve is analyzed. At the same time, the influence of the water level on the flow pattern of the spur dike is also discussed. It is concluded that after the dike group is arranged on the concave bank of the curve intersection at the curved intersection, the narrow flow can be bundled, the velocity distribution is optimized, the free surface form of the flow of the bend is changed, and the bend angle of the dike is changed to the curve intersection curve at the intersection angle and the water level. The influence of flow velocity has a certain influence. Under the condition of intersection angle and spur dike angle, the water level has a relatively small influence on the water surface shape near the spur dike, but it has a relatively large influence on the convex bank of the bend. It provides reference for further scientific research, engineering design, river regulation and other characteristics research.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV863

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