Basic and Practical Research on Flow Control in Open Channel Networks with Various Hydraulic Structures.

1.萨贺市开放通道网络系统调查萨贺市地区共26条通道，总长26661米。对该地区网络系统中的电线、收缩、闸门、涵洞和台阶也进行了调查。采用基于图论的分支节点模型，建立了通道网络非定常流场的数值模型。利用该模型，开发了各种水工结构的水工网络系统水力分析的计算机程序。该程序可以处理不做电路的盲通道、干通道和带泵的蓄水池。萨贺市明渠网络流量特性及改进方案(1)模拟萨贺市明渠网络在实测流量1.12m^3/s条件下的流量。该网络分为东网和西网两部分。两个部分仅通过一条通道连接。东部网络的流入率略占系统外总流入率的16%。这就导致了流动的停滞和干涸。也就是说，流速超过25cm/sec的分支数量略占分支总数的13%。速度在10cm/sec以下的分支约占40%，深度在5cm以下的分支约占30%。对目前的流动情况进行了很好的模拟和详细的把握。(2)东网改善流量情况的新增流量60%流入西网。通过堰流控制，速度在25cm/sec以上的分支数量增加到50%。已明确，进入该明渠网络的最合适的流入量为4.0-5.0m^3/秒。

1.Investigation of Open Channel Network Systems in Saga CityThe data for 26 channels with 26,661m long in total in Saga City area was collected. Wires, contractions, gates, culverts and steps in the network systems of this area were also investigated.2.Developments of Numerical Model and Computer ProgramNumerical model for unsteady flow in channel networks has been developed by using Branch-Node Model based on the graph theory. Using this model, the computer program for hydraulic analysis of channel network systems with various hydraulic constructions has been also developed. This program can treat the blind channel which does not make the circuit, the dry up channel and the reservoir with pump.3.Flow Characteristics and Improvement Plan of Open Channel Networks in Saga City(1) Flow of channel networks in Saga City was simulated under the condition of measured discharge, 1.12m^3/sec. The networks is divided into two parts, east and west networks. Two parts are connected by only one channel. The inflow rate to the east networks is slightly 16% of total one from the outside of system. This results in the stagnation and the dry up of flow. That is, the number of branches where the flow velocity exceeds 25cm/sec is slightly 13% of total number of branches. Moreover, branches with velocity under 10cm/sec is about 40% and branches with depth under 5cm is about 30%. The present flow situation has been perfectly simulated and grasped in detail.(2) The 60% of the additional amount of flow for improvement of the flow situation in the east networks flows into the west networks. The number of branches with velocity above 25cm/sec has increased to 50% by the flow control by a weir. It has been clarified that the most suitable inflow into this open channel networks is 4.0-5.0m^3/sec.