Numerical Study Of Mechanical Properties Of Circular Cross Section Plant Coupled With Two-dimensional Fluid Field

Fluid solid coupling problems exist widely in many engineering practices,such as housing and bridge engineer ing,marine engineer ing,windbreak engineering and so on.When the viscous fluid flows through a non-streamlined flexible solid structure,a periodical vortex street is formed behind the solid structure,which induces the fluid force that produces periodic changes,an d makes the solid structure vibrate.The vibration will change the flow field near the solid structure,and then influence the force of the fluid on the solid structure.This is the process of fluid solid coupling.The study of the interaction between fluid and solid structure,the maximum amplitude of the structure,the fluid force and its frequency composition,the characteristics of the flow field and the energy transport in the fluid solid coupling process will help to understand this process more deeply and provide theoretical support for the engineering practice.At present,most of the researches on fluid solid coupling problems are mainly based on experiments and less on numerical simulation.In this paper,the Fluent software is used to calculate the flow field in the coupling process of the circular cross section plant and the flow field.First,the Newmark-? method is improved.Then the program based on the Newmark-? method is embedded into the Fluent to realize the fluid solid coupling between a cylinder and the two-dimensional flow field,and to be used to calculate the column response.In the two-dimensional case,the numerical study of the coupling motion between the two degree of freedom cylinder and the flow field is carried out,and the variation of the column response and the characteristics of the flow field is analyzed under the different flow velocity and the system parameters.The main contents are as follows:1.First,the basic equations of the fluid solid coupling between the cylinder and the flow field are introduced,and the Newmark-? method for solving the vibration response of the cylinder is improved.The simulation results are in good agreement with the experimental results of Khalak and Williamson,which proves the rationality of the method used in this paper.Based on this,a numerical study of the coupling problem between cylinder and flow field in two-dimensional flow field is carried out.2.The mass ratio and the damping ratio of the system are two important factors affecting the flow and solid coupling process between the column and the flow field.The inf luence of the system mass ratio and the system damping ratio on the column response is studied in this paper.The influence of system mass ratio and damping ratio on maximum amplitude and fluid force is analyzed.3.Based on numerical results,the variation characteristics of flow field characteristics and energy transport characteristics under different system parameters are analyzed in this paper.The effective barrier of the cylinder to the fluid is defined,and the influence of the system mass ratio and the damping ratio of the system to the effective blocking interval is analyzed,which provides a theoretical basis for the selection of the material for the engineering w ind proof structure.