The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position ...The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.展开更多
圆筒型浮式生产储卸油装置(Floating Production Storage and Offloading,FPSO)较差的垂荡性能成为阻碍其走向深远海油气资源开发利用的一个重要因素,减动结构的设计能一定程度上改善垂荡性能。本文基于计算流体力学(Computational Flui...圆筒型浮式生产储卸油装置(Floating Production Storage and Offloading,FPSO)较差的垂荡性能成为阻碍其走向深远海油气资源开发利用的一个重要因素,减动结构的设计能一定程度上改善垂荡性能。本文基于计算流体力学(Computational Fluid Dynamics,CFD)的方法,利用Fluent软件建立三维数值水池模型,采用强迫垂荡运动的方式,计算了不同运动参数下带延伸筒体和减动结构的圆筒型FPSO的垂荡阻尼系数和附加质量。研究结果表明:垂荡阻尼系数与垂荡运动周期负相关,与垂荡运动幅值呈线性正相关,且垂荡运动周期较小时,垂荡阻尼系数受垂荡运动幅值的影响较明显。垂荡附加质量随着垂荡运动周期增大呈现明显上升趋势,但其对垂荡运动幅值不敏感。垂荡运动周期接近垂荡固有周期时,垂荡附加质量出现极小值。本文的计算结果能够为工程实际提供一定参考。展开更多
新能源发电并网系统的振荡问题是电网关注的重要研究课题,揭示振荡发生的机理并明确影响振荡的关键因素是首要研究任务。为此,建立了含静止无功发生器(static var generator,SVG)的光伏并网系统的小信号状态空间模型,通过特征值分析研...新能源发电并网系统的振荡问题是电网关注的重要研究课题,揭示振荡发生的机理并明确影响振荡的关键因素是首要研究任务。为此,建立了含静止无功发生器(static var generator,SVG)的光伏并网系统的小信号状态空间模型,通过特征值分析研究了光伏并网系统的主导振荡模式及与其强相关的动态环节,分析了交流侧系统对光伏并网系统振荡特性的影响;采用频率扫描法从电路谐振角度对光伏并网系统次同步振荡(subsynchronous oscillation,SSO)现象进行了解释,并通过时域仿真验证了特征模式分析结果的正确性。研究结果表明:含SVG的光伏并网系统存在一个主导SSO模式,光伏电站并网变流器的控制参数对该模式的稳定性具有重要影响;此外,SVG与光伏发电系统之间也存在相互控制作用,需要合理设计二者的控制参数,以提高系统整体的稳定性。研究内容可为光伏并网系统的运行和控制设计提供指导。展开更多
基金supported by the Tianjin Municipal Transportation Commission Project(No.2018-b2).
文摘The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.
文摘圆筒型浮式生产储卸油装置(Floating Production Storage and Offloading,FPSO)较差的垂荡性能成为阻碍其走向深远海油气资源开发利用的一个重要因素,减动结构的设计能一定程度上改善垂荡性能。本文基于计算流体力学(Computational Fluid Dynamics,CFD)的方法,利用Fluent软件建立三维数值水池模型,采用强迫垂荡运动的方式,计算了不同运动参数下带延伸筒体和减动结构的圆筒型FPSO的垂荡阻尼系数和附加质量。研究结果表明:垂荡阻尼系数与垂荡运动周期负相关,与垂荡运动幅值呈线性正相关,且垂荡运动周期较小时,垂荡阻尼系数受垂荡运动幅值的影响较明显。垂荡附加质量随着垂荡运动周期增大呈现明显上升趋势,但其对垂荡运动幅值不敏感。垂荡运动周期接近垂荡固有周期时,垂荡附加质量出现极小值。本文的计算结果能够为工程实际提供一定参考。
文摘新能源发电并网系统的振荡问题是电网关注的重要研究课题,揭示振荡发生的机理并明确影响振荡的关键因素是首要研究任务。为此,建立了含静止无功发生器(static var generator,SVG)的光伏并网系统的小信号状态空间模型,通过特征值分析研究了光伏并网系统的主导振荡模式及与其强相关的动态环节,分析了交流侧系统对光伏并网系统振荡特性的影响;采用频率扫描法从电路谐振角度对光伏并网系统次同步振荡(subsynchronous oscillation,SSO)现象进行了解释,并通过时域仿真验证了特征模式分析结果的正确性。研究结果表明:含SVG的光伏并网系统存在一个主导SSO模式,光伏电站并网变流器的控制参数对该模式的稳定性具有重要影响;此外,SVG与光伏发电系统之间也存在相互控制作用,需要合理设计二者的控制参数,以提高系统整体的稳定性。研究内容可为光伏并网系统的运行和控制设计提供指导。
