Investigation On Standard Of The Simulation Of Reynolds Number Effect Of High-flexible Structures With Circular Cross-section

The Reynolds number of the scale model in the wind tunnel test is much smaller than that of the full-scale structure in the atmospheric flow,and the difference of Reynolds number will make remarkable effect in the flow state and aerodynamic parameters of the circular cross-section structure,which is Reynolds number effect.For chimneys,TV towers and other high-rise and flexible structures with circular cross-sections that are prone to be damaged by wind,wind-resistant design is usually based on wind tunnel tests.To guarantee the reliability of wind-resistant design,it is necessary to ensure that the Reynolds number effect of the wind tunnel scale model and the actual structure is same,that is,the simulation of the Reynolds number effect.However,the existing research on the standard of the simulation of Reynolds number effect is not comprehensive,mainly in that the values of parameters such as root mean square lift coefficient and Strouhal number are not clear..Therefore,it is necessary to explore the values of the parameters related to Reynolds number effect.This paper summarizes the related parameters’data under high Reynolds number based on the field measurement of all kinds of circular cross-section structures.Then,the factors causing the differences between the measured data are analyzed.Finally,the value of simulation parameters in the range of high Reynolds number is established.The relevant results can provide reference for the wind tunnel test of circular cross-section structures.The main contents concluded are as follows:(1)The variation curves of root-mean-square lift coefficient and Strouhal number with Reynolds number in wind tunnel test are summarized.The range of Reynolds number is 40 to 10~7.It is found that there are great differences between different research,and the test data at high Reynolds number are limited.(2)All the reported measured data of circular cross-section structures are collected,including chimneys,cooling towers,TV towers,lighthouses and so on.A large number of measured data of the distribution of mean wind pressure,the distribution of fluctuating wind pressure,root-mean-square lift coefficient,and Strouhal number are obtained.The Reynolds number ranges from 4×10~5to 4×10~7.On this basis,the simulation parameters of mean pressure distribution and fluctuating pressure distribution under high Reynolds number are given,and it is found that the measured values of root mean square lift coefficient and Strouhal number are quite different from the wind tunnel test values,and there are some differences among the measured values of these two parameters in the same Reynolds number range.(3)The factors affecting the aerodynamic parameters of the structure include not only Reynolds number,but also turbulence and aeroelastic effect.In terms of turbulence,with the change of Reynolds number,the changes of root mean square lift coefficient and Strouhal number are also different;as far as aeroelastic effect is concerned,it is reflected in the influence of amplitude on aerodynamic parameters.According to the current research,the influence of aeroelastic effect can be ignored when the normalized amplitude of the structure is very small.(4)According to the measured data,the lift coefficient caused only by vortex shedding is calculated,and it is found that the lift coefficient shows the trend of"stability-rise-drop-stability",with the increase of Reynolds number in the transcritical range,and the relationship is fitted according to the data.According to the measured data of Strouhal number and the previous research,it is found that the Strouhal number did not change with Reynolds number and turbulence,and remain steady at about 0.22in the transcritical range.