A parametric study of the galloping stability of two-dimensional triangular cross-section bodies

One of the classical aeroelastic instabilities of slender structures is galloping, which can be characterized as a low-frequency, large-amplitude normal to the flow oscillations phenomenon.In this paper the effects of cross-sectional shape and mean wind angle of incidence on the transverse galloping stability (according to the Glauert–Den Hartog criterion for galloping instability) of triangular cross-section bodies has been systematically analyzed through static wind tunnel experiments. Nine triangular cross-section models were tested, the angle at the main vertex, β  , ranging from 10° to 90°. In addition, three additional models having rounded corners have been tested, to check the impact of a modification in windward corners in modifying the flow pattern around the cross-section, facilitating eventually the reattachment of the boundary layer and narrowing therefore the width of the wake. Static tests confirm that the stability to transverse translational galloping of triangular cross-section cylinders are both cross-sectional geometry and angle of attack dependent, the potential unstable zones in the angle of attack–main vertex angle plane (α,β)(α,β) being identified.