极端流态溃坝过程中水体流速与流量变化的模拟研究

Simulation study of water velocity and discharge varies in the dam break process of extreme flow pattern

针对城市景观水体源水流量小、流动性差而导致水体恶化的现状,提出了模拟溃坝水流以增大流速冲淤的技术——缓蓄快放系统,介绍了缓蓄快放系统的基本原理和特点。以概化的西安市护城河为例,进行微缩物理模型试验,同时利用溃坝水流理论进行模拟计算。结果表明,模型试验实测断面最大流量与谢任之公式计算结果的相对误差为-22.0%^-2.9%,实测最大水深与计算结果相对误差在-13.6%~13.3%。将模型试验数据按照比例进行放大,得出在西安市概化护城河上建立1.0m蓄水深度条件下,溃坝水流发生后,下游距闸门2 000.0m范围内各断面最大流量达到0.5m^3/s以上,水流平均流速在0.75m/s以上,缓蓄快放系统能够增大下游瞬时流量,提高断面流速,使水体达到不滞留的目的。

In view of the current situation of water quality deterioration caused by the small flow and illiquid of city landscape water,slow storing and quick draining system was proposed on the basis of simulation of dam break to improve quality of landscape water. Meanwhile, the basic principle and feature of this system was introduced. A mini ature physical model was exampled as the generalized Xi^an moat and an simulation experiment was carried out. Com- pared the calculated results of XIE Renzhi formula with model measured, the relative error of maximum discharge quantity was between --22.0% and --2.9% ,and for water depth was between 13.6%and 13.3%. The data from experiments were amplified through the scale,the dam flow when the system in generalized Xi＇an moat under depth of 1.0 m was calculated. The rate of flow within 2 000.0 m from gate was more than 0.5 m3/s, the average flow velocity was greater than 0.75 m/s, the water flow and the velocity were greatly enhanced by the low storing and quick drai- ning system.