A Nonlinear Model for Wind-Induced Oscillations of Trees

• Main Author: Ramanujam, Lakshmi Narayanan
• Format: Others
• Published: ScholarWorks@UMass Amherst 2012
• Subjects: fluid-structure interactions; wind; trees; nonlinear; structural; dynamics; Other Mechanical Engineering
• Online Access: https://scholarworks.umass.edu/theses/943; https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=2065&context=theses

Ambient wind causes trees to oscillate. Wind-induced oscillations of trees constitute a fluid-structure interaction problem, which has been studied by many researchers from various points of view. However, there is yet a lot to be done. From an engineering point of view, the complex structure of trees, which are very different from man-made structures, as well as the highly nonlinear interaction between wind and tree, makes it a challenging task to predict the amplitude and frequency of the resulting oscillations. From a biological point of view, the influence of wind on photosynthesis as well as the growth and death of plants is crucial. A nonlinear model is derived for wind-induced oscillations of trees to investigate the effect of structural nonlinearities. It is shown that the structural nonlinearities in the system can result in a hardening behavior of the tree, indicating the importance of taking such nonlinearities into account. The influence of various system parameters such as tree’s age, taper and slenderness ratio on the tree oscillations is studied using this nonlinear model.