流致振动是影响顶张式立管群工作性能重要因素。工程实际中主要采用单相内流模型和串列布置式的Blevins尾流干涉模型进行分析，缺乏针对内外流共同作用下的立管群流致振动特性的深入研究。本项目首先开展基于扩展有限元法的（XFEM）顶张式立管群内外流流致振动数值模拟研究，在二维圆柱绕模型的基础上发展内外流作用下的流致振动数值模拟方法。然后引入气液两相流模型，研究含气率、两相粘性比等参数对立管振动特性的影响；扩展Blevins模型，将两串立管尾流干涉模型推广到多立管串联和交叉布置的应用场合；进而建立内外流共同作用下的顶张式立管群流致振动解析模型；应用L-W“流管“模型研究立管间的振动影响。利用实验研究为解析模型的建立提供合理边界和水动力系数的确定方法并验证数值分析和解析模型。最后分析不同立管布置形式、阻尼比及节距比等参数影响下的顶张式立管群的振动特性，并得到流致振动稳定图。

Flow induced vibration (FIV) is an important factor affects the working capacity of top tension riser array (TTRA). In industry, single-phase flow model and Blevins model are used generally, but lack of the model to explain the FIV characteristics of TTRA under both two-phase internal and external flow. This program firstly will carry out a study on the FIV numerical simulation method (NSM) of TTRA under internal and external flow based on extended finite element method (XFEM), which is developed from 2D-model of cylinder FIV. Then the model of gas-liquid two-phase flow will be introduced to show the affect of gas bearing ratio and viscosity ratio on FIV of TTRA. The Blevins model will be devloped from two risers in tandem configuration to multi-riser and intersect configuration. The L-W "streamtube" model will be used to study the mutual effect of FIV bwteen the risers of TTRA. The experimental study will be carried out to provide reasonable boundary conditions and hydrodynamic coefficients to the analytical model and verify the NSM and analytical model. At last, the effects of TTRA configurations, damping ratio, pitch ratio on the FIV characteristics of TTRA will be studied, and the diagram of FIV stability will be obtained.