FLOW INDUCED ROTATION OF A FLAT PLATE SUBJECTED IN UNIFORM CURRENT BASED ON THE STREAMLINE THEORY

摘要

This work describes the behavior of a vertical flat plate free to rotate in uniform current. The intention of this research is to study the fluttering problem that may occur with falling objects in water such as a manifold during the pendulous installation method (PIM). The free streamline theory is applied here to investigate the steady, two-dimensional flow at a given angle of attack past a flat plate with a fully developed wake. The leading and trailing edges of the plate are assumed to be sharp and the flow configurations are such that the free streamlines separate from the plate at these sharp edges, the thickness of the flat plate is assumed to be of zero. The Roshko's model will be used to approximate the wake far downstream. The moment coefficient formulation has been calculated for different angles of attack yielding good accuracy with experimental results. This includes the existence of a natural frequency for small amplitude oscillations. The free-streamline theory confirms that the natural frequency is linearly proportional to the incoming flow velocity.