An analysis on the dependence on cross section geometry of galloping stability of two-dimensional bodies having either biconvex or rhomboidal cross sections

Galloping is a well-known type of aeroelastic instability, but still difficult to predict as the relevant experimental data must first be obtained. Available information on non-rectangular cross-sections is scarce and non-systematic. The purpose of the present paper is to add new information gathered through static wind tunnel experiments. The effects of cross-sectional shape on the transverse galloping stability (according to the Glauert–Den Hartog criterion for galloping instability) of biconvex and rhomboidal cross-section bodies have been systematically analyzed. Measuring the aerodynamic coefficients and the pressure distributions along the body surfaces permits a better understanding of the galloping phenomenon and how the aerodynamic characteristics of the bodies evolve when changing parametrically the cross-section geometry from the known-case of the flat plate to the also known square or circular prisms. As a result of these investigations the potential unstable zones in the angle of attack – cross-section aspect ratio plane (α,t/cα,t/c) are identified.