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1.
3-D direct current resistivity forward modeling by adaptive multigrid finite element method 总被引:1,自引:1,他引:0
Based on the fact that 3-D model discretization by artificial could not always be successfully implemented especially for large-scaled problems when high accuracy and efficiency were required, a new adaptive multigrid finite element method was proposed. In this algorithm, a-posteriori error estimator was employed to generate adaptively refined mesh on a given initial mesh. On these iterative meshes, V-cycle based multigrid method was adopted to fast solve each linear equation with each initial iterative term interpolated from last mesh. With this error estimator, the unknowns were nearly optimally distributed on the final mesh which guaranteed the accuracy. The numerical results show that the multigrid solver is faster and more stable compared with ICCG solver. Meanwhile, the numerical results obtained from the final model discretization approximate the analytical solutions with maximal relative errors less than 1%, which remarkably validates this algorithm. 相似文献
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本文对龙溪河梯级水电站长期存在的枢纽工程等级划分及设计标准,设计洪水及其地我组成,联合防洪、发电调度运行,以及分期设计洪水、分期防洪、发电运行的可靠性问题,根据我国现行各有关规范的要求和方法,结合本流域水文特生及该梯级工程现况与运行实践,进行了全面系统地复核,研究,获得了令人满意的成果。复核研究不仅使工程等级标准不协调,设计洪水地区组成、污期联合防洪、发电调度运行的不合理,以及防洪与发电的矛盾等, 相似文献
3.
分期设计洪水分析计算及防洪发电控制运行 总被引:1,自引:1,他引:0
四川龙溪河梯级和大洪河电站水库一直沿用常规设计所确定的防洪,发电运行方式,从而造成汛期大量弃水,往往汛末蓄不满,枯水期末又消落不到死水位,使各电站的发电数量和质量受到影响,将洪水以8月1日为界,分前期后期进行分期设计洪水计算,并据此进行分期防洪,发电控制运行,不仅能满足各防护对象的洪水标准及控制要求,还留有一定的安全裕度,增加的发电经济效益和社会效益较为显著,实践证明这一方法可行,值得深入探讨研究 相似文献
4.
电磁法勘探以电磁感应原理为基础,主要通过观测到的电磁场响应推断地下电阻率的空间分布特征,在此基础上结合地质解释,从而实现金属矿产勘查的目的。目前,电磁法按照接收信号组成分为频率域与时间域两大类,勘探深度从浅部几米到深部几十公里,应用领域从陆地、高空到海洋均有涉及。本文简要综述了主要电磁勘探方法理论、应用场景及观测系统,从数据解释角度回顾了电磁法正演模拟与反演计算研究工作,介绍了不同种类电磁法在金属矿勘查中的典型应用案例,最后对电磁法勘探金属矿的发展提出了作者的看法和建议。 相似文献
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我国最早建成的龙溪河梯级水电站,是在我国尚无工程等级标准规范,参照前苏联建筑法规,分别确定的主要建筑物级别和设计标准.由于该梯级电站工程等级标准不协调,已成建筑物不配套,给联合防洪调度带来诸多困扰,也影响了一定的发电效益.在1990年、1995年先后分批完成大坝首次定期安全检查期问,首先根据我国现行工程等级标准等规范的有关规定,结合建筑物和运行管理的实况,对该梯级电站的工程等级、设计标准、设计洪水、联合防洪调度、坝顶安全超高等,全面系统地进行了复核分析工作,成果令人满意,已通过正式鉴定. 相似文献
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大洪河水电站自建成投产30多年来,有关水库防洪的种种问题一直未能得到圆满解决。在电站首次大坝定期安全检查工作期间,又针对水库防洪安全问题进行了一次较为全面深入地分析研究以及治理对策方案的综合比较。推荐在结合现有正常溢洪道需要加固补强的同时,降低溢流堰顶高程以扩大泄洪能力的治理方案,经鉴定认为该方案切实可行。现已完成工程设计并竣工投入运行。 相似文献
8.
A finite element algorithm combined with divergence condition was presented for computing three-dimensional(3D) magnetotelluric
forward modeling. The finite element equation of three-dimensional magnetotelluric forward modeling was derived from Maxwell’s
equations using general variation principle. The divergence condition was added forcedly to the electric field boundary value
problem, which made the solution correct. The system of equation of the finite element algorithm was a large sparse, banded,
symmetric, ill-conditioned, non-Hermitian complex matrix equation, which can be solved using the Bi-CGSTAB method. In order
to prove correctness of the three-dimensional magnetotelluric forward algorithm, the computed results and analytic results
of one-dimensional geo-electrical model were compared. In addition, the three-dimensional magnetotelluric forward algorithm
is given a further evaluation by computing COMMEMI model. The forward modeling results show that the algorithm is very efficient,
and it has a lot of advantages, such as the high precision, the canonical process of solving problem, meeting the internal
boundary condition automatically and adapting to all kinds of distribution of multi-substances.
Foundation item: Project(60672042) supported by the National Natural Science Foundation of China 相似文献
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大地电磁法主要依据视电阻率及相位曲线的形态特征来分析大地电性分布,因此阻抗张量的计算十分重要。在实际探测中,噪声的存在使得计算得到的阻抗张量往往存在一定的偏差,干扰了数据解释的准确性。本文概述了大地电磁阻抗张量计算方法的发展,首先介绍了现在常用的几种大地电磁阻抗计算方法及其不足之处,然后介绍了如何利用两种Jackknife方法来判断阻抗估计的稳定性。 相似文献
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龚嘴水电站设计洪水与防洪安全的复核研究 总被引:1,自引:0,他引:1
龚嘴水电站建成投产20余年来,由于水库泥沙淤积严重,总库容已减少62.9%;施工期间坝下沿河大量堆碴,厂房尾水水位抬高1.6-3.0m,对大坝特别是厂房等的防洪安全问题,令人担忧和关注。在本电站首次大坝安全定期检查中,要求对设计洪水与厂房尾水位-流量关系线,以及大坝、厂房、拦漂设施与成昆铁路的防洪安全问题,进行一次全面系统的复核研究。结果表明,根据现行规范的规定,调整洪水标准后,各防洪保护对象沿尚 相似文献