【作者】 张芹；

【导师】 张小峰；

【作者基本信息】 武汉大学 ， 水力学及河流动力学， 2005， 硕士

【摘要】 随着洪灾频繁的发生,作为防洪工程体系中重要组成部分的分滞洪区在江河防洪中已发挥着重要作用,因此,正确模拟计算分滞洪区洪水演进尤为重要,在模拟计算分滞洪区时,分洪口门的流量变化过程是要解决的问题之一。目前,分洪口门的流量通常是通过堰流公式来进行计算的,在恒定堰流出现淹没出流时,最小流量不为零;而在分洪区计算时,随着分洪区内水深的逐渐抬高,当分洪区内水位跟外江河道水位基本持平时,分洪口门的进洪流量为零,因此,此时用堰流来进行分洪口门的流量计算是不可行的。本文将通过平面二维水流数学模型来研究分蓄洪区口门的流量变化规律。 论文共分为五章,各章主要内容如下: 第一章 明确本文的研究内容,介绍了洪水演进计算、分洪区计算以及堰流计算的研究现状,对洪水演进的主要计算方法进行了叙述,且对水动力学中常用的求解水流运动方程的数值方法也进行了详细的叙述。 第二章 简要介绍了平面二维水流数学模型的基本方程,并用所建立的数学模型模拟计算恒定堰流和概化分洪区的计算,从计算结果可以看出,平面二维水流数学模型模拟计算恒定堰流是可靠的;同时从分洪区的模拟计算中可以看出:随着分洪区内水深的逐渐增大,分洪口进流由自由出流变为淹没出流,且进洪流量随着淹没程度的增大而逐渐减小,当分洪区内水位跟外江河道水位基本持平时,分洪口进洪流量产生小幅度振荡且最后趋于零。 第三章 从几个可能的影响因素方面来分析分洪口的进洪流量情况,即找出流量系数以及洪水演进情况的主要影响因素,通过分析可知,流量系数的主要影响因素为相对堰高和堤顶宽度。 第四章 进行了淹没系数的几个可能影响因素糙率、相对堰高、口门位置、口门宽度等的敏感性分析,分析结果表明:淹没系数的主要影响因素为淹没程度和相对堰高。然后运用回归分析方法求出了流量系数、淹没系数与各自主要影响因素之间的回归方程。 第五章 对全文进行了总结并对以后的工作进行了展望。更多还原

【Abstract】 As one important part of the flood control system, the flood diversion area plays an very important function in the flood control project, and it is very important to model the flood routing in the flood diversion area. When modeling the flood diversion area, one problem that needs to be solved is to model the discharge variation process at the entrance of the flood diversion area. Now, the discharge at the entrance is usually calculated by weir formula, and when the submerged discharge appeared, the minimum flow is larger than zero, but with the water depth boost gradually, when the water depth equals to that of the river, the inflow at the entrance equals to zero during calculating the flood diversion area, so its is absurdity to calculate the discharge with weir formula. In this paper, the horizontal 2-D numerical model is applied to model the rule of discharge variation at the entrance of the flood diversion area.Particular contents in five chapters are presented as follows:Chap.l The object and aim of study in the paper is given, and it summarizes the current research situation of flood routing and Flood diversion area calculating and Flow over weir calculating. And the main methods of flood routing are recounted, As well as the numerical methods in common use to describe flow movements in hydrodynamics have been introduced detailed in the paper.Chap.2 The equation of the two-dimension current numerical model is introduced simply, and using the established numerical model to simulate the steady flow over weir and simulative Flood diversion area, Seen from the result calculated, It is credible to use the two-dimension current numerical model to simulate the steady flow over weir; At the same time, From the simulation of Flood diversion area we can get the following conclusion: with the depth increased, The entering current is changed from freedom to submerged, and the discharge by the gateway is gradually reduced with the increase of the submerged extent, When the water level in the Flood diversion area is equal to which in watercourse, the value of discharge is zero.Chap.3 It analyses the course of discharge of gateway from a few possible influencing factors, That is to find out the main influencing factors of Coefficient of discharge and flood routing, The results indicate that the main influencing factors of Coefficient of discharge are the opposite depth and the length of the weir.Chap.4 It analyses the main influencing factors of submerged coefficient from afew possible influencing factors, Such as roughness ?> relative height of weh% the location and width of gateway etc, The results indicate that the main influencing factors of Submerged coefficient are the opposite depth and the submergence extent. Then using the method of regression analysis to seek the regression equation of Coefficient of discharge and Submerged coefficient with each influencing factors.Chap. 5 It sums up the whole paper and prospect further research work.更多还原