基于最小外接矩形的宗地四至赋值程序设计与实现     

王保国  苏小东 《测绘》2020,43(3):134-136

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RANS Modeling of Solitary Wave Propagation over A Submerged Rectangular Breakwater     

Tai-Wen HSU  Chin-Yen TSAI 《中国海洋工程》2009,23(3):473-488

In this paper a series of numerical simulations are performed to investigate the vortex shedding mechanism for a solitary wave propagating over a submerged breakwater by use of Reynolds averaged Navier-Stokes (RANS) model combined with a k-ε model. Flows of different Reynolds numbers up to Re=1.4×105 corresponding to varying incident wave heights are considered in which the characteristic fluid velocity is represented by the maximum horizontal velocity above the submerged breakwater. For the verification of...  相似文献   

Isoparametric Boundary Element Method Applied to the Rectangular and Delta Hydrofoils near the Free Surface     

Hassan GHASSEMI  Ahmad Reza KOHANSAL 《中国海洋工程》2010,24(2):321-331

In this paper, the hydrodynamic characteristics and flow field around rectangular and delta hydrofoils, moving with a constant speed beneath the free surface are numerically studied by means of isoparametric boundary element method (IBEM). The quantities (source and dipole strengths) and the geometry of the elements are represented by a linear distribution. Two types of three-dimensional hydrofoils (rectangular and delta) are selected with NACA4412 and symmetric Joukowski sections. Some numerical results of pressure distribution, lift, wave-making drag coefficients and velocity field around the hydrofoils are presented. Also, the wave pattern due to moving hydrofoil is predicted at different operational conditions. Comparisons are made between computational results obtained through this method and those from the experimental measurements and other numerical results which reveal good agreement.  相似文献   

Study on Failure Mechanism and Bearing Capacity of Three-Dimensional Rectangular Footing Subjected to Combined Loading   总被引：2，自引：0，他引：2  

张其一  栾茂田  王忠涛 《中国海洋工程》2008,22(2):313-330

This paper presents two kinematic failure mechanisms of threc-dimensional rectangular footing resting on homogeneous undrained clay foundation under uniaxial vertical loading and uniaxial moment loading. The failure mechanism under vertical loading comprises a plane strain Prandti-type mechanism over the central part of the longer side, and the size of the mechanism gradually reduces at the ends of the longer side and over the shorter side as the corner of rectangular footing is being approached where the direction of soil motion remains normal to each corresponding side respectively. The failure mechanism under moment loading comprises a plane strain scoop sliding mechanism over the central part of the longer side, and the radius of scoop sliding mechanism increases linearly at the ends of the longer side. On the basis of the kinematic failure mechanisms mentioned above, the vertical ultimate bearing capacity and the ultimate bearing capacity against moment or moment ultimate bearing capacity are obtained by use of upper bound limit analysis theory. At the same time, numerical analysis results, Skempton＇ s results and Salgado et al. ＇s results are compared with this upper bound solution. It shows that the presented failure mechanisms and plastic limit analysis predictions are validated. In order to investigate the behaviors of undrained clay foundation beneath the rectangular footing subjected to the combined loadings, numerical analysis is adopted by virtue of the general-purpose FEM software ABAQUS, where the clay is assumed to obey the Mohr-Coulomb yielding criterion. The failure envelope and the ultimate bearing capacity are achieved by the numerical analysis results with the varying aspect ratios from length L to breadth B of the rectangular footing. The failure mechanisms of rectangular footing which are subjected to the combined vertical loading V and horizontal loading H （Vertical loading V and moment loading M, and horizontal loading H and moment loading M respectively are observed in the finite e  相似文献   

考虑注浆作用的矩形顶管竖向土压力计算模型          下载免费PDF全文

周浩  周千淼  谈力昕  张鹏  马保松 《地质科技通报》2021,40(2):125-130

针对矩形顶管上竖向土压力计算模型研究较少的现状，借助Terzaghi土压力计算理论，结合矩形顶管工程特点建立了考虑注浆作用的矩形顶管竖向土压力计算模型，提出了改进的竖向土压力计算公式；依托苏州某矩形顶管工程中竖向土压力实时监测数据，探究了其变化规律并验证了该计算公式的准确性。研究结果表明:土体中的剪切带从管道外壁两侧产生并沿竖直方向发展，且可贯穿至地表；临界状态下剪切带上的膨胀角完全发挥，以临界内摩擦角及其正弦值计算剪切带上的摩擦系数；不同的注浆压力下，管道上方可能出现“主动土拱”和“被动土拱”。计算值与实测值的对比分析表明，改进后的计算方法能够较好地包络矩形顶管竖向土压力范围。   相似文献   

矩形容器中流体晃动等效模型的建议公式     

李遇春  来明 《地震工程与工程振动》2013,33(1):124-127

根据矩形容器中流体晃动等效模型的精确解,采用非线性拟合算法,给出了等效模型中脉冲质量及其位置的拟合公式,本文给出的拟合公式比精确解简单、且计算精度远高于Housner公式,可以作为精确解良好的替代公式。建议采用本文公式(3)～(8)作为矩形容器内流体晃动等效模型的计算表达式。  相似文献   

基于道路外包矩形的移动终端自适应匹配算法     

潘超超  周晓光  阳成飞 《测绘信息与工程》2013,38(1):23-26

首先通过外包矩形与定位点坐标确定候选道路遍历范围,然后通过计算包含定位点的道路外包矩形个数自动判断其所处路段是简单或交叉路段,继而对简单路段采用垂直投影,交叉路段采用历史轨迹进行匹配。最后采用c#语言实现了该算法,并与两类常用算法对比,验证了其优越性。  相似文献   

矩形隧道结构的地震动力破坏研究     

魏晓刚  刘会丽  杨柳川  王占阳  李广慧  刘书贤  法靖宇 《地震研究》2022,(3):405-415

为深入研究地震作用下矩形隧道结构的动力响应变化规律,得到隧道结构的失稳破坏机制,通过建立土一隧道结构协同作用的整体力学模型,采用大型室内振动台实验与有限元数值计算对比分析的方法,重点探讨了地震作用下土-隧道结构整体力学模型的加速度时程、频谱特性、位移及土压力等方面的力学响应。研究发现：振动台实验与数值模拟计算的结果变化...  相似文献   

渗透海床上矩形Bragg防波堤对波浪反射的研究     

倪云林  龚倩  沈梦佳 《海洋学报》2022,44(9):124-131

与海床不可渗透的情况相比,波浪在可渗透海床上传播时会发生波能衰减。本文将基于可渗透海床上一维修正型缓坡方程,建立方程求解的有限差分模型。将通过与不可渗透海床上矩形Bragg防波堤对波浪反射系数解析解的对比,验证有限差分模型的正确性和适用性。将进一步研究海床可渗透情况下,海床的渗透性参数、坝体的相对宽度、数量、浸没度对波浪反射系数的影响及其与海床不可渗透情况下的差异。本文研究发现,Bragg共振发生时的反射系数随坝体数量的增多而增大,随海床渗透性参数和坝体浸没度的增大而减小,并且存在一个坝体相对宽度值会使Bragg共振反射达到最大。相较于海床不可渗透的情况,发生Bragg共振反射的波浪频率几乎相同,但反射系数减小,而且零反射（或全透射）现象不再存在。  相似文献   

高速铁路CPⅢ高程控制网测量方法研究   总被引：4，自引：0，他引：4  

李书亮  刘成龙  倪先桃  徐小左 《测绘科学》2011,36(1):45-47,16

本文分析高速铁路CPⅢ高程控制网建网时普遍采用的德国测量方法,指出其存在的不足,在此基础上提出了技术上更为合理又适合我国国情的矩形法测量方法。通过对矩形法相邻点高差相对中误差和最弱点高程中误差的估算以及实验验证,认为矩形法可以用于CPⅢ高程网的建网测量。研究结果对于目前高速铁路工程测量相关规范的制订和在建高速铁路CPⅢ高程网的测量具有重要的参照价值。  相似文献