A methodology for the experimental extraction of indicial functions for streamlined and bluff deck sections

This paper addresses the experimental derivation of step-response non-stationary forces in the time domain (indicial functions), to be used in iterative numerical simulations (convolution techniques) for flutter instability analyses of suspension bridges, as an alternative to aeroelastic derivatives evaluated in the frequency domain. In particular a system, conceived for the direct extraction of these coefficients, has been designed, built and tested in wind tunnel. The study has investigated the experimental procedure of measurement and the statistical analysis of the recorded data. Both airfoil-type models (NACA) and a bluff section, simulating the behavior of bridge section, have been considered.