FUNDAMENTAL STUDY ON THE EFFICIENCY OF POWER GENERATION SYSTEM BY USE OF THE FLUTTER INSTABILITY

摘要

Recently, Isogai et al.[l] proposed a new idea on power generation by use of flutter instability of thin airfoil. The heaving steady oscillation, which produces the electrical power from wind energy, can be excited by the forced torsional oscillation initially given to the heaving and torsional 2DOF system at any wind velocity ranges in his study. On the other hand, the authors have investigated the coupled flutter mechanism of various bluff bodies from the point of two different torsional and heaving branches by use of the "Step-by-Step flutter analysis method" (abbreviated by the SBS method).[2,3,4] Isogai's idea is identical to the heaving branch flutter in the SBS method. Thus, the improvement of the power generation performance is investigated in this paper basing upon the flutter mechanism, and the efficiency of power generation by use of the heaving branch flutter was compared with that by the torsional branch flutter. It has been clarified that the obtained energy by the heaving oscillation would be larger than the supplied energy for giving initial torsional oscillation to the system and loss-energy caused by the structural damping and the aerodynamic damping over certain wind velocity range.