共查询到20条相似文献,搜索用时 171 毫秒
1.
维持控制点水位稳定是保证输水渠道安全有效运行的前提.以控制点水位偏差为主要抑制因子,基于线性二次型(LQR)指标,构建了渠道系统水位偏差、偏差变率和流量控制的全状态空间模型,将加入预测模块的线性二次型算法在渠道系统的全状态空间中进行分析和综合,提出了扰动可预知模型的构造方法.通过脉冲响应测试来加深对算法结构的理解,使用南水北调中线电子渠道平台对算法有效性进行验证,验证结果表明,该算法在渠道运行工况改变后,仍能够维持渠道的稳定运行,算法设计极具潜在的应用价值. 相似文献
2.
提出了一种针对自流型渠道输水的最优化控制的两步法。第一步是控制各闸站流量使渠段水位(或蓄水量)达到目标水位(或蓄水量),第二步是调整流量使渠段水位稳定。建立了使渠道内水流在最短时间内恢复到正常运行水位的最优渠道输水控制模型。构建了长距离渠道输水控制的一系列约束条件,包括渠道下游需水量约束、最高控制水位、水位最大容许下降速度、渠道容许过流能力、最少的开机次数等。提出了利用线性规划或将大系统分解为若干子系统求解的方法。算例结果表明,用传统的渠道控制方法需要几天才能使水位恢复到目标水位的渠道,用本优化方法控制,可以在几小时内使渠道水位达到目标水位并达到稳定。 相似文献
3.
4.
5.
非饱和土粒间毛细水作用是其基质吸力的主要来源。本文基于二维非连续变形分析算法(DDA),建立了一种能够模拟不同饱和度下毛细水分布状态及计算土水特征曲线的扩展DDA算法。该算法首先通过反复迭代的方式来计算出不同饱和度下毛细水弯液面的半径,并利用圆心轨迹交汇法确定粒间毛细水弯液面与颗粒的搭接位置,从而确定各个颗粒表面被毛细水浸湿的区域。而后利用Young-Laplace方程计算出各个浸湿区域毛细负压的大小,并将其与表面张力添加到传统DDA算法控制方程中。为验证该算法,参照真实黄土中含量最多的粗颗粒建立一理想黄土微观土骨架模型,模拟了不同饱和度下土体中的毛细水分布状态,并获得了土水特征曲线。将模拟结果与实测的土水特征曲线进行对比分析,结果显示预测值和实测值基本一致,该方法能够从微观上揭示非饱和土粒间吸力作用的本质。 相似文献
6.
7.
针对中国北方海湾水库间歇来水、连续取水和沉积物动态释盐的特点,建立水量与盐分耦合的数学模型,以青岛拟建的沐官岛水库为例,探讨水位变化条件下混合型海湾水库库水盐分的影响因素、超标风险与达标条件。模拟结果表明,在水库水位连续降低条件下,毫米量级的日蒸发量对库水盐分的累积效应显著。在不利水文条件下,受沉积物释盐、水分蒸发与人工取水的影响,混合型海湾水库长期存在盐分超标的风险。与水位不变时相反,水位降低时库水盐分浓度随着取水量的增大而升高;因此,当库水盐分存在超标风险时,可以通过减少日取水量实现库水盐分达标。为保障安全供水,在海湾水库设计与运营管理阶段,均需要综合考虑水量-盐分因素进行水库的日取水量调算。 相似文献
8.
9.
本文较详细地介绍多变量时间序列模型方法在沉积动力学方面的应用.利用线性最小二乘回归算法确定系统辨识模型的未知参数矩阵.针对实际数据(河口数据)的模拟结果显示,这种方法是预测河口悬浮沉积浓度和沉积输运的合适方法. 相似文献
10.
广西覆盖型岩溶区土层崩解机理研究 总被引:12,自引:1,他引:12
根据广西覆盖型岩溶区原状土样和扰动土样的室内试验结果, 研究土的崩解与土的矿物成分、化学成分、结构、颗粒大小、物理性质、含水状态和水的化学成分、水位变化等因素的关系。 相似文献
11.
12.
13.
为准确预测区域水资源承载力的变化趋势和制定优化的调控方案,从"经济社会-水资源-生态环境"系统互馈机理出发,建立水资源承载力水量、水质、水域空间、水流的全要素诊断体系,识别关键驱动指标;采用支持向量机、系统动力学等多种方法,建立水资源承载力定量动态预测模型,同时制定调控目标,结合分析驱动指标的实现难易程度和代价,采用正交试验方法,优选承载力提升和减负方案。应用于黄河流域水量要素承载力的诊断、预测与调控,结果表明,南水北调西线工程等调水工程运行前各规划水平年黄河流域、上游区、中游区、下游区均处于超载或严重超载状态,运行后均处于临界超载或超载状态,选择非常规水利用、入海水量、亩均灌溉用水量、灌溉面积、万元工业增加值用水量、工业增加值等6个关键驱动指标,进行正交试验,得到了各水平年水量承载力均不超载的最优调控方案,可为黄河流域水资源管理工作提供指导。 相似文献
14.
引大入秦工程是由大通河向甘肃中部兰州市永登县秦王川地区跨流域引水的以农业灌溉为主要目的大型调水工程。工程建成通水后,对改变当地农业生产条件和贫困面貌、安置贫困山区移民、促进秦王川地区的经济社会发展发挥了重要作用。但是,由于各种因素的综合影响,工程在设计效益的发挥等方面存在一些问题,集中表现在供水能力未能充分发挥、工程水资源配置没有实现最优化。在收集到翔实的第一手资料的基础上,将引大灌区和周边可能的供水范围作为一个统一的研究对象即引大工程供水区,根据供水区的供需水现状和用水发展趋势,采用水资源系统分析理论中的最优化技术,建立以经济效益、社会效益和环境效益最优为目标、以供需水量为约束条件的优化配置模型,通过求解模型,确定近期和远期供水区的水资源在各子区不同用水部门间的最优化配置方案,为富余水源寻找出路,这对最大限度地发挥工程效益,促进区域经济社会的可持续发展具有重要作用。 相似文献
15.
针对多水源多作物灌区,研究有限供水条件下灌区优化配水问题。模型中既考虑水库优化调度,又考虑田间优化配水。模型思路:根据灌区水土资源分布状况,将全灌区划分为多个子区,每个子区种植有若干种作物。如果把每个子区每种作物所在的田块看作一个土壤水库,则可采用水库群调度的方法研究这类灌区优化配水问题,文中采用的是优化控制方法。为了证明模型的正确性,同时建立了3个模型。模型1:既不考虑水库优化调度又不考虑田间优化配水;模型2:只考虑水库优化调度;模型3:只考虑田间优化配水。实例计算表明,整合调度模型能产生较多的效益(特别在干旱年份),优化控制方法计算性能良好。 相似文献
16.
Werapol Bejranonda Manfred Koch Sucharit Koontanakulvong 《Environmental Earth Sciences》2013,70(5):2079-2086
Many irrigation projects in the central plain of Thailand are not capable of providing sufficient surface water for the cultivation of rice, which is the major cash crop for Thai farmers. To overcome this surface water deficiency, which has been exacerbated in recent years by climate change, groundwater is increasingly being used for irrigation. Thus, large sections of agriculture lands have been converted to conjunctive water use regions. While conjunctive water use may be a suitable option to overcome the temporary water shortages on a short-term basis, it may pose a particular threat to the overall water resources in the long term, if not properly managed. As a remedy, conjunctive water management policies ought to be adopted. Conjunctive water management is basically a tool to optimize productivity, equity, and environmental sustainability through simultaneous management of surface water and groundwater resources. As of now, such a comprehensive approach has not been yet employed in the upper Chao Phraya basin of Thailand, and the present study is one of the first of this kind. The study region is the Plaichumpol Irrigation Project (PIP) where conjunctive water use has become indispensable for meeting the increasing water requirements for farming. To get a first grip on the issue, water demand, supply and actual use in the study area were investigated for the purpose of providing possible guidelines for optimal water exploitation. A numerical groundwater model with a special module for simulating surface-groundwater interaction was applied in the PIP area to understand the impact of the farmer’s irrigation behavior on the dominant hydrological processes that determine the seasonal and multi-annual water availability in the irrigation area. A set-up of different agricultural water allocation schemes that depend on the local weather conditions and the regional management rules are examined by the numerical models. The results of the simulations provide adaptation guidelines for the proper management of the conjunctive water resources, namely, optimal water utilization. The numerical results for the surface groundwater in particular indicated that while the irrigation canals recharge water to the aquifer during both dry and wet season, small amounts of discharge from the aquifers to the canals occur only during the wet season. The analysis of the groundwater balance also showed that the present available groundwater potential is not fully exploited by the farmers, especially during the dry periods of surface water shortage. In contrast, the adoption of an optimal conjunctive management scheme would ensure extra water availability for additional annual rice crops in the region. 相似文献
17.
18.
针对以往在建造各类作物生长模拟模型中,对构成作物整体功能的根、冠关系这一系统未予(充分)考虑的现状,在整体、器官水平上,探讨、分析了根、冠之间相互关系,归纳了根、冠系统各种特性,并构建了以土壤水分作为调控因子的根、冠互相藕合机制模型。模型辨识及两年冬小麦试验数据验证结果表明,该模型具有较强普适性和较高模拟预测精度,不仅能模拟预测出不同土壤水分条件下根、冠干物重,研究根、冠间互利互制消长反馈关系,而且还可根据不同生产目标规划灌溉方案。 相似文献
19.
The aim of this paper is to present an application of robust inverse Nyquist array control design method to a milling circuit in Majdanpek Copper Mine. An existent model of a milling circuit was adopted to respond to robust inverse Nyquist array methodology demand by introducing model uncertainty, and optimal robust controller of milling circuit is designed. The proposed controller is robust for reference signals. The robustness of multivariable feedback systems with designed controller is tested and compared with different, previously designed multivariable controllers. Simulation results, in time domain, demonstrate the preferable performance of the designed robust controller in setpoint tracking. Implementation of the new controller without any investments in new equipment significantly improves performance of the milling process. 相似文献
20.
Niels Schütze Sebastian Kloss Franz Lennartz Ahmed Al Bakri Gerd H. Schmitz 《Environmental Earth Sciences》2012,65(5):1511-1521
In this contribution, we introduce a stochastic framework for decision support for optimal planning and operation of water
supply in irrigation. This consists of (1) a weather generator for simulating regional impacts of climate change on the basis
of IPCC scenarios, (2) a tailor-made evolutionary optimization algorithm for optimal irrigation scheduling with limited water
supply, (3) a mechanistic model for simulating water transport and crop growth in a sound manner, and (4) a kernel density
estimator for estimating stochastic productivity, profit, and demand functions by a nonparametric method. As a result of several
simulation/optimization runs within the framework, we present stochastic crop-water production functions (SCWPF) for different
crops which can be used as a basic tool for assessing the impact of climate variability on the risk for the potential yield
for specific crops and specific agricultural areas. A case study for an agricultural area in the Al Batinah region of the
Sultanate of Oman is used to illustrate these methodologies. In addition, microeconomic impacts of climate change and the
vulnerability of the agro-ecological system are discussed. 相似文献