Wind-induced Response Of Trees And Its Effect On Wind Pressure Distribution In Low-rise Buildings

With the development and progress of social economy and technology,more and more attention has been paid to the construction of ecological civilization in China.The concept of "Lucid waters and lush mountains are invaluable assets" is going deep into people’s hearts.The roadside trees in the city leave us a green space.It is of great significance to explore the reconfiguration,force and other performance of the tree under strong wind and its influence on the wind pressure of the surrounding buildings such as low-rise buildings.Firstly,According to the current research status of wind-induced response of roadside trees,four specific living trees were used to simulate the roadside trees,and the wind tunnel balance test was carried out.The relationship between wind speed and aerodynamic characteristics of four model trees,such as frontal area,porosity,drag and drag coefficient is obtained.It is concluded that the frontalarea of the model tree decreases in a power function relationship with the increase of wind speed;The drag coefficient of each model tree shows a decreasin-g trend when the wind speed increases.Secondly,Study the influence of model trees on average and fluctuating wind pressure of low buildings.The contour diagram of wind pressure on each surface of low-rise building and the curve change diagram of wind pressure after partition are given under the influence of different model trees and different distance.The results show that the mean wind pressure coefficient of low-rise buildings will decrease,but the fluctuating wind pressure coefficient will increase.And because of the interference effect of the model tree,the fluctuating wind pressure in the extreme value of the lowrise building will increase;When the distance between the model tree and the low-rise building changes,the influence of each model tree on the wind pressure of the low building varies.This indicates that the crown shape,stiffness and height of tree species have a great influence on the interference effect of low-rise buildings.Finally,Study the spectral characteristics of downwind drag in four model trees.The results showed that the maximum low frequency power of Camellia model tree with the maximum change of frontal area was obtained.Maximum vibrational energy in Middle and High Frequency bands of Jiulixiang 8 nian miao;The probability characteristics of the downwind drag of the four model trees are analyzed.It is found that the drag of each model tree accords with the Gaussian characteristic when the wind speed changes.This provides a positive and useful reference value for the design of low-rise houses.