Numerical simulation of wind-driven circulation and pollutant transport in Taihu Lake based on a quadtree grid

In this study,a two-dimensional flow-pollutant coupled model was developed based on a quadtree grid.This model was established to allow the accurate simulation of wind-driven flow in a large-scale shallow lake with irregular natural boundaries when focusing on important smallscale localized flow features.The quadtree grid was created by domain decomposition.The governing equations were solved using the finite volume method,and the normal fluxes of mass,momentum,and pollutants across the interface between cells were computed by means of a Godunov-type Osher scheme.The model was employed to simulate wind-driven flow in a circular basin with non-uniform depth.The computed values were in agreement with analytical data.The results indicate that the quadtree grid has fine local resolution and high efficiency,and is convenient for local refinement.It is clear that the quadtree grid model is effective when applied to complex flow domains.Finally,the model was used to calculate the flow field and concentration field of Taihu Lake,demonstrating its ability to predict the flow and concentration fields in an actual water area with complex geometry.     

近60多年洞庭湖水沙演变特征及其与人类活动的关系

基于1955—2018年洞庭湖水沙数据,运用Mann-Kendall检验法、双累积曲线等方法分析了洞庭湖近60多年水沙演变特征及其与人类活动的关系.研究结果表明:①受长江荆江段河道变化以及水利枢纽建设等的影响,三口、四水入洞庭湖水沙呈显著下降趋势,其中以三口输沙量的变化最为显著,且受三口水沙变化的影响,城陵矶年径流量与...     

不同水动力情况下青山湖水环境治理方案研究

根据南昌市青山湖浅水湖泊紊流扰动特性,建立相应的沿水深方向平均的二维平面水流-水质模型.模型在有限体积法框架下应用Osher黎曼近似解进行平面二维水流-水质模拟,理想资料检验表明,模型性能优良.模拟不同调水方案对青山湖水质的改善状况,为城市浅水湖泊水流-水质模拟提供可操作的新途径.     

水质综合评价的模糊可变模型及其应用

水质综合评价是一个涉及多指标、多级别、考虑区间值的模糊评价问题,将模糊可变集理论引入其中,在评价数学模型不变的前提下,用熵值法、等权法和单纯阈值法3种方法确定指标权重,并以东昌湖为例,分析了各方法对应的级别特征值的稳定性,最终确定各样本的评价等级,结果表明模型的合理性和实用性.     

长江中游涨渡湖的水平衡分析与研究

在识别和计算所有入流和出流成分的基础上,建立了涨渡湖的水平衡方程和模型,分析了当前平常年该湖的总水量增减状况。然后,在气候变化研究以及由此归纳出的未来可能出现的气候变化情景下,对2030、2050、2080和2100年的年度湖水位变化趋势进行了预测,同时对未来可能出现的干旱和极端干旱情景进行了水的可获得性(可用性)风险分析。     

试论淮河实施河湖分离的必要性及可行方案

针对长期以来人们只认知洪泽湖的几十亿立方米防洪调蓄能力,却漠视它的河湖串阻力及其一级尾闾地位的情况,通过对历史洪水和有关资料的分析,初步揭示平原河湖串的危害性,由此引证进一步治理淮河实施河湖分离的必要性,并提出一种合理的河湖分离方案,以及比较可行的模拟论证方法.     

太湖底泥总磷含量特征分析

对2002年10月至2003年1月期间太湖全湖223个监测点不同深度采集的共583个底质样品测定的有机质和总磷含量数据进行了分析．分析表明,不同深度处底泥总磷含量平均值相差不大．除第六层以外,不同深度处底泥总磷含量最大值相差也不大．综合前人资料,比较可知,20世纪80年代以来太湖底泥表层沉积物总磷含量平均值变化不大,但最大值逐次增加．研究还分析了底泥总磷含量与有机质含量相关性特点．     

洞庭湖区电排站前池防渗处理措施探讨

由于特殊的地质地貌条件和水特性,在洞庭湖区电排站的前池和进水渠经常存在渗漏和管涌现象,导致电排站前池和站房出现不均匀沉陷和开裂,严重已危及到大堤的防洪保安．以屈原垸推山咀电排站为例,经过理论分析计算和不同方案的技术经济比较,推荐采用钢筋混凝土铺盖方案对前池进行加固处理．经2003年和2004年洪水的考验,防渗效果良好．     

Optimal reservoir operation using Nash bargaining solution and evolutionary algorithms

Optimizing reservoir operation is critical to ongoing sustainable water resources management. However, different stakeholders in reservoir management often have different interests and resource competition may provoke conflicts. Resource competition warrants the use of bargaining solution approaches to develop an optimal operational scheme. In this study, the Nash bargaining solution method was used to formulate an objective function for water allocation in a reservoir. Additionally, the genetic and ant colony optimization algorithms were used to achieve optimal solutions of the objective function. The Mahabad Dam in West Azerbaijan, Iran, was used as a case study site due to its complex water allocation requirements for multiple stakeholders, including agricultural, domestic, industrial, and environmental sectors. The relative weights of different sectors in the objective function were determined using a discrete kernel based on the priorities stipulated by the government (the Lake Urmia National Restoration Program). According to the policies for the agricultural sector, water allocation optimization for different sectors was carried out using three scenarios: (1) the current situation, (2) optimization of the cultivation pattern, and (3) changes to the irrigation system. The results showed that the objective function and the Nash bargaining solution method led to a water utility for all stakeholders of 98%. Furthermore, the two optimization algorithms were used to achieve the global optimal solution of the objective function, and reduced the failure of the domestic sector by 10% while meeting the required objective in water-limited periods. As the conflicts among stakeholders may become more common with a changing climate and an increase in water demand, these results have implications for reservoir operation and associated policies.     

白洋淀水温变化规律研究

依据白洋淀数字化地形图,结合白洋淀地区年平均气温变化数据,对白洋淀的水温变化规律进行了数值模拟。模拟表明：在水生生物最佳生长水位时（以大沽高程8．0m为例）,（1）白洋淀水温在水平方向上（表层以下）分布具有差异,8月前,浅水区水温较高,深水区水温较低。8月后,水平温度分布不再有差异。（2）水温垂向分布呈现分层现象。7月下旬前,垂向分层由不规则逐渐向具有规则性发展,深水区分层数稍多于浅水区分层,7月底8月初,分层极具规则性。8月中旬,垂向水温达到一致,没有分层现象,9月后,又出现新的分层．（3）表底温差在8月初一直存在,浅水区表底温差小于深水区的。8月中旬,表底温差消失,9月初重新出现。（4）从动力学、热力学的角度研究了白洋淀的水温变化规律。