CFD calculations of indicial lift responses for bluff bodies

Two-dimensional formulations for wind forces on elongated bodies, such as bridge decks, are reviewed and links with expressions found in two-dimensional airfoil theory are pointed out. The present research focus on indicial lift responses and admittance functions which are commonly used to improve buffeting analysis of bluff bodies. A computational fluid dynamic (CID) analysis is used to derive these aerodynamic functions for various sections. The numerical procedure is presented and results are discussed which demonstrate that the particular shapes of these functions are strongly dependent on the evolution of the separated flows around the sections at the early stages.