Stability Analysis of a Yawing Flat Plate Into the Water Current

The present study deals with the stability analysis of an oscillating flat plate into the water current. The flat plate, which is attached to a torsion spring and located vertically in the water current, has only 1 DOF that is yawing motion. The experiments have shown that as the current velocity exceeds a special threshold, the flat plate becomes unstable and begins to oscillate. This oscillation can be utilized to extract energy. A free vibration experimental technique is used in this study. The experimental results are analyzed using the flutter derivative theory, in which the flutter derivatives of the motion are extracted using GLS (General Least-Square) method. The results confirm that the flat plate becomes dynamically unstable. Also, there is a Liapunov stable fixed point on the origin at the phase portrait of the yawing motion.