Numerical Simulation Of Fluid-structure Interaction Of Transmission Line

Structures become more and more light and flexible because modern buildingstructures develop to be super high-rise and large span. Under the wind loads, thefluid-solid interaction effect to the structure is very conspicuous. For powertransmission system, the large span conductor has a small stiffness, a small dampingand characteristic of strong coupling of structure and fluid. Besides the application ofbuilding structures and power transmission, fluid-solid interaction plays an importantrole in the application of bridge cable and pipeline, and has important academic valueand wide application prospect.Under the wind loads, no matter circular cross-section or non-circular cross-sectioncylinder will give rise to the aerodynamic forces and then start the vibration. Currently,the research of structure vibration mainly forces on single-phase fluid-structureinteraction neglecting the interaction between fluid and structure under wind loads. Thecomputational fluid dynamics (CFD) is employed in present paper to study the circulartransmission line section and iced transmission line section’s characteristics and laws offlow-induced vibration under a uniform inflow. The research work of this paper ismainly focus on the following three aspects:Firstly, to realize numerical simulation of fluid-structure interaction, fluid domainis calculated by FLUENT. A computation program of the structural domain is realizedthrough a User Defined Function (UDF) based a Newmark-β algorithm in a C languageenvironment. The boundary updating is conducted through a moving-grid technology.The effect of the fluid domain, the quality of mesh, the time-step, the parameter settingof moving-grid and self programming on calculation’s accuracy and efficiency areinvestigated. A numerical calculation method of flow-induced vibration of a rigidcylinder under an elastic support is realized with high reliability and high efficiency.Secondly, to achieve the low-induced vibration law of the cylinder at lowRe, anumerical calculation method of flow-induced vibration of a rigid cylinder under anelastic support is adopted. The variation of the structure parameters and the flow-alongvibration with the aerodynamic forces and oscillation displacements are emphaticallyanalyzed. The cylinder oscillation displacements variation with structure parameters andDOF are achieved. The correlation among the aerodynamic forces, the wake vortexstructures and cylinder vibration is revealed. Thirdly, to realize the numerical simulation of a fixed cylinder under highRe,structured grid is generated by ICEM. Fluid domain is calculated with FLUENT. Thesuitable turbulence model, time-step, mesh’ quality, the fluid domain are suggested. Thenumerical simulation of a fixed under highRe is realized, which laid the foundation ofnumerical simulation of fluid-structure interaction at highRe.Fourth, to achieve the iced transmission line cross-section law of flow-inducedvibration at lowRe, a numerical calculation method of flow-induced vibration of a rigidcolumn under an elastic support is adopted. The influence of structure parameters andthe degree of freedom of the model on the aerodynamic forces and oscillationdisplacement are emphatically analyzed. The cylinder oscillation displacement lawswith structural parameters and DOF are obtained. The system vibration process fromgalloping to vortex-induced vibration is displayed. The correlation among aerodynamicforce, the wake vortex structures and cylinder vibration is revealed.