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三维I型超长管线阴极保护的数值模拟 总被引:1,自引:1,他引:1
研究超长管线阴极保护设计问题的数学模型和数值模拟,并将介质电阻、金属面电阻及金属自身电阻作了系统处理。通过数值试验与实验结果的对比,肯定了所提出的数学模型及所用边界元法在处理此类问题时的合理性及有效性。 相似文献
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海洋钢结构阴极保护电场的数值模拟仿真和计算是当前海洋腐蚀、阴极保护研究和工程实践中一个重要的研究方向。研究海底管线的腐蚀状态就必须准确测定管线表面的电位分布,而实际测量中深海管线表面电位分布难以直接测量。构建了海水中钢管线的阴极保护数学模型,采用以边界元法为基础的数值计算方法,利用Matlab开发了均匀电解质中电位分布的计算软件,实测中通过对腐蚀电场海水区域环境电场的测量,就可实现不接触测量管线表面电位的目的。最后通过海洋实测验证了计算结果的可靠性,证明了基于Matlab的数值仿真计算引入阴极保护设计中是行之有效的。 相似文献
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基于势流理论提出一种新的高阶边界元方法对无限水深的聚焦波浪进行完全非线性数值模拟.自由水面满足完全非线性边界条件,模拟波浪的非线性效果可以达到更高阶.利用镜像原理,建立一种全新的格林函数应用到无限水深的数值波浪水槽中,以致于两无限深水槽侧壁的积分可以被排除.为了产生相应的入射波和吸收出流波浪,一个由点源组成的造波装置被布置于计算域内,同时人工阻尼层被用来吸引出流波浪,由波浪聚焦的方法得到极限波浪.通过开展线性和完全非线性聚焦波浪的数值实验及与理论解对比,验证本数值模型可以用来模拟无限深水域的极限波浪,且在出流边界没有反射. 相似文献
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By introducing a source term into the Laplace equation, a two-dimensional fully nonlinear time-domain numerical wave flume (NWF) is developed to investigate the resonance induced by the interaction bet... 相似文献
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通过表面观察及电化学方法研究X80钢在含有SRB的海水溶液中阴极保护准则的适用性,测试结果表明:腐蚀控制因素为阳极控制,对金属施加阴极极化第5天降低金属腐蚀速度主要通过增大金属表面SRB的附着电阻和电荷转移电阻实现;而施加阴极极化第10天,阴极保护主要通过改变金属表面电荷转移电阻控制腐蚀速度,且阴极极化电位越大控制效果越好。无阴级保护的金属试样腐蚀产物较多且附着力差,施加阴极保护的金属试样腐蚀产物较少且附着力较强。阴极保护的确能对存在SRB的海水溶液环境中X80钢起到阴极极化作用,但极化5 d时传统的阴极保护准则中-850 mVCSE(即-770 mVSCE)电位未达到85%的保护要求,-950 mVCSE(即-870 mVSCE)电位刚刚能满足保护要求;而极化10 d时2种极化电位下保护度都有所下降且都不能满足保护要求,因此还需要进一步实验确定其合适的阴极保护电位。 相似文献
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A time-domain higher-order boundary element scheme was utilized to simulate the linear and nonlinear irregular waves and diffractions due to a structure. Upon the second-order irregular waves with four Airy wave components being fed through the inflow boundary, the fully nonlinear boundary problem was solved in a time-marching scheme. The open boundary was modeled by combining an absorbing beach and the stretching technique. The proposed numerical scheme was verified by simulating the linear regular and irregular waves. The scheme was further applied to compute the linear and nonlinear irregular wave diffraction forces acting on a vertical truncated circular cylinder. The nonlinear results were also verified by checking the accuracy of the nonlinear simulation. 相似文献
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Waves generated by vertical seafloor movements are simulated by use of a fully nonlinear two-dimensional numerical wave tank. In the souree region, the seafloor lifts to a designated height by a generation function. The numerical tests show that the linear theory is only valid for estimating the wave behaviors induced by the seafloor movements with a small amplitude, and the fully nonlinear numerical model should be adopted in the simulation of the wave generation by the large amplitude seafloor movements. Without the background surface waves, many numerical tests on the stable maximum elevations η0^max are carried out by beth the linear theory and the fully nonlinear model. The results of two models are compared and analyzed. For the fully nonlinear model, the influences of the amplitudes and the horizontal lengths on η^max are stronger than that of the characteristic duration times. Furthermore, results reveal that there are significant differences be- tween the linear theory and the fully nonlinear model. When the influences of the background surface waves are considered, the corresponding numerical analyses reveal that with the fully nonlinear model the η0^max near-linearly varies with the wave amplitudes of the surface waves, and the η0^max has significant dependences on the wave lengths and the wave phases of the surface waves. In addition, the differences between the linear theory and the fully nonlinear model are still obvious, and these differences are significantly affected by the wave parameters of the background surface waves, such as the wave amplitude, the wave length and the wave phase. 相似文献
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Freak waves are generated based on the mechanism of wave focusing in a 2D numerical wave tank. To set up the nonlinear numerical wave tank, the Boundary Element Method is used to solve potential flow equations incorporated with fully nonlinear free surface boundary conditions. The nonlinear properties of freak waves, such as high frequency components and wave profile asymmetry, are discussed. The kinematic data, which can be useful for the evaluation of the wave forces exerted on structures to avoid underestimation of linear predictions, are obtained, and discussed, from the simulated results of freak waves. 相似文献