摘要
为了探索树木在风场中摇曳的运动机理,建立了风中摇曳树木的有限元模型.采用圆柱绕流的涡致振动理论估算了树枝在风中因旋涡脱落而引起的脉动升力和阻力;用基于任意拉格朗日欧拉法(ALE)的流固耦合模拟方法估算了不同风速和树叶角度的情况下风施加在树叶上的作用力;用基于圆柱绕流实验数据的简化流固耦合模拟方法估算了树枝大变形后作用在树枝上的风荷载变化.模拟结果表明,考察节点均以环状的方式运动,并且两种不同风场中的轨迹非常类似.由旋涡的脱落而引起的枝条抖动频率很高,但振幅很小.不同枝条之间存在相互的影响,并能改变考察点的运动轨迹.
A finite element model of swaying tree was established to explore the kinetic mechanism of swaying tree in wind field. The fluctuate drag and lift forces of tree branches in wind due to vortex shedding were estimated using the vortex induced vibration theory of circular cylinder. An arbitrary Lagrange-Eulerian （ALE） based fluid-structure interaction method was used to calculate the wind force exerted on a leaf under various wind speeds and leaf angles. A simplified fluid-structure method based on the experimental data of circular cylinder in flow field was proposed to estimate the variation of wind load on the tree bran- ches due to large deformation. Simulation showed that the investigated nodes are all moving in a looping manner, and the trajectories under two different wind fields are very similar. The branches are shaking in high frequencies due to the vortex shedding on branches, but the amplitudes are very small. Different branches interact with each other, and can change the motion trajectories of the investigated points.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2008年第7期1123-1127,共5页
Journal of Zhejiang University：Engineering Science
关键词
摇曳
有限元
流固耦合
涡致振动
swaying
finite element
fluid-structure interaction
vortex induced vibration
