Peculiar aspects of flow-induced vibration of rectangular sections subjected to air and water flows

The present work summarizes some findings arisen from two distinct experimental investigations carried out on sharp-edged rectangular cylinders with low side ratio (SR) in air and water flow. The chosen section, SR=1.5, was tested into two distinct facilities conducting static and dynamic experiments. Several sectional models were tested also imposing an angle of attack of 90°, to get information about the behaviour of the SR=0.67. Static tests revealed strong differences in the aero- and hydrodynamics, in particular with respect to the proclivity to the galloping instability. These results were then confirmed by aero- and hydroelastic experiments, underlying quite different behaviour of the same geometry characterized by mass ratios separated by the same order of magnitude existing between air and water density.