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The chain/wire rope/chain combination is a commonchoice for mooring offshore floating platforms. However, data ofthe drag coefficients of chain links are rather limited, resulting inuncertainties with the calculations of the drag force, and hence thedamping of the mooring system. In this paper, the importance of theselection of the drag coefficient is first investigated. Thecomputational fluid dynamics (CFD) method is then used todetermine the drag coefficients of a studless chain under steadyflows. Numerical model validation is first completed by simulatinga smooth circular cylinder under steady flows. In particular, theperformance of different turbulence models is assessed through thecomparisons between the calculations and the experimental results.The large eddy simulation (LES) model is finally selected for thesimulation of steady flows past a chain. The effects of the Reynoldsnumber on the drag coefficient of a stud-less chain is also studied.The results show that the calculated drag coefficients of a stud-lesschain are fairly consistent with the available experimental data. 相似文献
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This paper discusses the numerical modeling of the dynamic coupled analysis of the floating platform and mooring/risers using the asynchronous coupling algorithm with the purpose to improve the computational efficiency when multiple lines are connected to the platform. The numerical model of the platform motion simulation in wave is presented. Additionally, how the asynchronous coupling algorithm is implemented during the dynamic coupling analysis is introduced. Through a comparison of the numerical results of our developed model with commercial software for a SPAR platform, the developed numerical model is checked and validated. 相似文献
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This work presents an analysis of the fleet size determination problem for a truckload distribution center in which each customer requests multi‐truckload services. A transformation is made to define this problem as a cutting stock problem which can be resolved by finding the proper set of patterns beneficial for an NP‐hard (non‐deterministic polynomial‐time hard) problem. The genetic algorithm (GA) is combined with cutting stock techniques to solve the problem. Experiments are carried out testing two types of problems, with and without time‐window constraints. To verify the solution quality obtained with the proposed approach, the problem is also solved using only GA. It is shown that the proposed approach can significantly improve the GA solution by 14.68%. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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针对目前独柱匝道桥梁结构研究中存在的问题,结合独柱匝道桥梁结构的力学特性,明确影响独柱匝道桥梁安全性的各种因素,采用层次分析法(AHP)建立独柱匝道桥梁结构的安全评估模型。最后,针对独柱匝道桥梁的结构特点及各种病害产生原因,探讨匝道桥梁结构的科学运营管理方法,为桥梁管理部门的日常管理、养护提供参考。 相似文献
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