Research On The Aerodynamic Characteristics Of Platanus Acerifolia Tree Leaves

In this paper,the aerodynamic characteristics of platanus acerifolia leaves were studied by experimental methods.With the increase of wind load,platanus acerifolia leaves have different shape.To find the main factors which affect the critical wind speed and resistance coefficient of platanus acerifolia leaves by change the size of leaf and petiole.Research the vibration frequency and amplitude of the leaves and wake flow field distribution of the leaves.Experimental methods include high-speed camera recording,wind tunnel bala nce test,particle image related vibration measure vibration,hot wire anemometry and particle Imaging velocity measure wake flow.Through analysis the real platanus acerifolia leaves' area,the ratio of petiole length and width,we found that the critica l Reynolds number is a function of leaf area and petioles' length to width ratio.By changing one of the influencing factors: petiole length,petiole width,thickness and size of leaf area,for artificial platanus acerifolia leaves the critical velocity is a function of leaf area,leaf thickness,petiole length and petiole width.The drag coefficient of real p latanus acerifolia and artificial platanus acerifolia leaves decreased with the increase of Reynolds number and finally approaches between 0.1-0.3.leaf area and petiole length are important factors of influencing the resistance coefficient for artificial platanus acerifolia leaves.With the wind speed increases,the vibration frequency of the artificial platanus acerifolia leaves in three directions o f the UVW was coincident,but the vibration amplitude was different.When the leave is stable and static,wake of real leaves and the artificial leaves have a stable vortex shedding.When the leave is in vibration,the frequency of the vortex shedding frequency increases and appears resonance frequency.With the increase of wind velocity,the size of the vortex becomes smaller.