Suppression of Galloping Oscillations Using Perforated Bluff Bodies

This study explores the potential effect of utilizing perforated bluff bodies on suppressing galloping oscillations. Six types of perforated bluff bodies with vertically parallel two holes, four holes, and six holes are proposed, and three kinds of surface treatments including all-sided and non-all-sided designs are implemented to vary the perforated shape. A comprehensive aero-electromechanical mathematical modelling is established for better analysing the proposed passive vibration suppression system. Wind tunnel experiments and numerical simulations reveal that increasing the number of holes on perforated bluff bodies can effectively reduce the vibration amplitude and increase the galloping cut-in wind speed. Furthermore, only the all-sided six-hole perforated bluff body has the greatest potential to suppress galloping oscillations. Further wind tunnel computational fluid dynamics (CFD) simulations are also performed to obtain the transverse force coefficients so as to investigate the underlying aerodynamic reasons behind the observed phenomena. Compared with most of the existing galloping oscillations suppression methods, this technique has the advantages of no external energy, lightweight, and simple design, etc., which makes it promising for possible practical applications.