共查询到18条相似文献,搜索用时 46 毫秒
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为模拟淹没丁坝群平面二维水流运动,提出了淹没丁坝群二维水流数值模拟新方法并建立了数学模型。新方法的主要实施方案:① 将丁坝视为无厚度坝,用网格线概化丁坝;② 采用新的网格节点布置形式,即水深、流速节点布置于网格界面上,水位节点布置于网格中心,有别于一般交错网格节点布置。模型采用基于结构网格下的有限体积法对方程组进行离散,同时将淹没丁坝坝顶水深代入离散方程中进行求解。采用已有的水槽试验资料,进行了初步验证,模拟了长江下游东流水道已建丁坝群工程实施后河道的流场和水位场,结果表明计算和实测符合较好。 相似文献
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太湖流域河网水流运动模拟研究 总被引:1,自引:0,他引:1
本文在以往研究的基础上,利用距离提取陆域宽度,采用最短路径法,考虑河道过水面积、流量模数等因素,对陆域面上的调蓄作用进行相似模拟.为减少计算工作量,避免受计算机容量、计算工作量及资料的限制,对天然河网湖泊进行合并及概化,考虑区域工程情况及其运行方式以及破圩后的水流情况,建立了河网水流运动模型,在太湖流域防洪调度中得到了应用. 相似文献
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针对城市河网缺乏足够的实测资料和河网水动力学模型模拟速度慢的特点,提出将河网水动力学模型与遗传算法、神经网络方法结合,建立河网智能模型。模型中,利用河网水动力学模型提供神经网络所需的信息,遗传算法用于优化神经网络的初始权重。将该模型应用于上海市浦东新区河网中,智能模拟结果与经过实测资料验证的河网水动力学模型的模拟结果吻合较好,表明河网智能模型精度与水动力学模型接近。同时实时性较好,可用来预测河网水位变化特性,也为今后类似研究提供一种模拟技术。 相似文献
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与顺直明渠水流相比,明渠交汇水流由于存在分离区和自由剪切面,其紊动特性引起的阻力较为复杂,交汇水流除床面阻力外还受到较强的阻力。基于数值模拟与实验比较分析表明,分离流与自由剪切流所产生的阻力(紊动粘性阻力)对于交汇水流数值模拟具有重要影响。同时,由于平面二维模型对二次流影响的忽略,断面环流较强时数值模拟会产生较大的阻力(环流阻力),而断面环流较弱时,交汇水流的三维特性相对较弱,采用平面二维模型和k-ε紊流模型能达到较好的模拟效果。因此,紊动及环流阻力的计算对交汇水流数值模拟的精度至关重要。 相似文献
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《水文地质工程地质》2007,34(1):I0005-I0005
中国水利水电科学研究院开发研制了地表水和地下水资源评价系列应用软件。全部软件基于Windows环境,完全可视化操作界面。软件系统适合于各类水体环境、地下水源地或区域地下水资源评价和预测预报。软件实用高效,在国内已拥有众多用户,并得到用户一致好评。 相似文献
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Semi-two-dimensional numerical model for river morphological change prediction: theory and concepts 总被引:2,自引:2,他引:0
Tew-Fik Mahdi 《Natural Hazards》2009,49(3):565-603
This paper presents a new numerical model for river morphological predictions. This tool predicts vertical and lateral cross-section
variations for alluvial rivers, which is an important task in predicting the associated hazard zone after a flood event. The
Model for the HYdraulics of SEdiments in Rivers, version 1.0 (MHYSER 1.0) is a semi-two-dimensional model using the stream
tubes concept to achieve lateral variations of velocity, flow stresses, and sediment transport rates. Each stream tube has
the same conveyance as the other ones. In MHYSER 1.0, the uncoupled approach is used to solve the set of conservation equations.
After the backwater calculation, the river is divided into a finite number of stream tubes of equal conveyances. The sediment
routing and bed adjustments calculations are accomplished separately along each stream tube taking into account lateral mass
exchanges. The determination of depth and width adjustments is based on the minimum stream power theory. Moreover, MHYSER
1.0 offers two options to treat riverbank stability. The first one is based on the angle of repose. The bank slope should
not be allowed to increase beyond a certain critical value supplied to MHYSER 1.0. The second one is based on the modified
Bishop’s method to determine a safety factor evaluating the potential risk of a landslide along the river bank. 相似文献
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为解决河道水动力模拟中由于局部急、缓流态交替可能导致计算不稳定、模拟过程无法实施的问题,提出根据实际河段存在的缓流、急流、水跌以及水跃4种流态,采用基于特征线、水量平衡等原理在各流态分界处添加内部边界的思路,建立基于Preissmann方法的复杂流态自适应模拟模型。所构建的模型能保持Preissmann方法的特点,即相邻断面离散模板以及河道首末断面各需给定一个边界条件,该特点有利于方法直接与现有成熟河网水动力模型连接。理想算例的计算结果表明方法能够模拟急、缓流之间的渐变过渡;而石亭江的实际算例表明在急、缓流态频繁交替时,采用单河道模式及河网模式均能收敛到恒定状态,满足模拟实际复杂流态时的稳定性要求。 相似文献
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This paper reports on the numerical modelling of flash flood propagation in urban areas after an excessive rainfall event or dam/dyke break wave. A two-dimensional (2-D) depth-averaged shallow-water model is used, with a refined grid of quadrilaterals and triangles for representing the urban area topography. The 2-D shallow-water equations are solved using the explicit second-order scheme that is adapted from MUSCL approach. Four applications are described to demonstrate the potential benefits and limits of 2-D modelling: (i) laboratory experimental dam-break wave in the presence of an isolated building; (ii) flash flood over a physical model of the urbanized Toce river valley in Italy; (iii) flash flood in October 1988 at the city of Nîmes (France) and (iv) dam-break flood in October 1982 at the town of Sumacárcel (Spain). Computed flow depths and velocities compare well with recorded data, although for the experimental study on dam-break wave some discrepancies are observed around buildings, where the flow is strongly 3-D in character. The numerical simulations show that the flow depths and flood wave celerity are significantly affected by the presence of buildings in comparison with the original floodplain. Further, this study confirms the importance of topography and roughness coefficient for flood propagation simulation. 相似文献