Numerical Stimulation And Theoretical Analysis Of Flow Around Stay Tube

The stay tube with circular section is widely used in container crane, crawler crane and other construction machineries. This kind of component usually has a big slenderness ratio, which could probably make wind-induced-vibration occurs. The strong vibration, however, can cause the fatigue cracking of rod's both-end . Under the action of wind and rain, there will form rivulet with cyclical motion in the surface of stay tube, which can cause large amplitude of stay tube. This is a special type of wind-induced vibration which is called wind-rain induced vibration. It could cause much larger amplitude than other types of vibration. In this paper, it mainly studies stay tube's wind-rain-induced vibration by means of numerical simulation and theoretical analysis. The main work includes as follows:(1) The study mainly researches the influence of angle position of rivulet on flow around the stay tube by means of numerical simulation. Firstly, establishing the computational model and setting the boundary condition. Then, applying the Reynolds stress model (RSM) to make the numerical simulation on different rivulet positions by means of ANSYS CFX 11.0 computational fluid dynamics software, and getting the change law of distribution of surface pressure, lift coefficient and drag coefficient along with the angle position of rivulet. Finally, comparing the data with the former's test data to verify the validity of the numerical simulation;(2) Choosing the Reynolds stress model (RSM) to make numerical simulation of flow around stay tube with four different size of rivulet. Then getting the flow characteristics and analyzing the influence of rivulet size on the surface coefficient of aerodynamic of stay tube;(3) Analyzing the slipstream around the stay tube by numerical simulation that adopts standard k—εmodel and Reynolds stress model .Then, analysis contrasting the results of two models demonstrates that Reynolds stress model is better. Meanwhile, the analyzing result provides reference to adopt turbulence model;(4) Setting up the SODF model of stay tube and using MATLAB software to write program for solving the differential equation of stay tube movement basing on fourth order Runge-Kutta method. Computing the program to analyze the effect of the initial angle position of rivulet, natural frequency of stay tube, inlet wind speed U₀, spatial attitude of stay tube (inclinationα, wind angleβ), which influence the vibration of the stay tube. Then the comparison between the analytical results and the experimental data was carried out to demonstrate the validity of theoretical analysis.