The Kinematics of Wheat Struck by a Wind Gust

A nonlinear model of the kinematics of a wheat stalk struck by a wind gust is developed. Individual stalks were excited from each of many directions and observed by videophotography. The underdamped flexural response involved anisotropic circling motion that can be reproduced by a nonlinear system of ODEs. In the model, the horizontal path traveled by the grain mass is described in principal coordinates XI and XII. The four required constants are stiffnesses kI