2D Aerodynamic Admittances of a Streamlined Box Bridge Deck in Various Turbulent Flows

Abstract

Due to the influence of the three-dimensional (3D) effect, the identification accuracy of 3D aerodynamic admittance functions (AAFs) would inevitably be influenced by the ratio of turbulent integral scale to model dimension (dimensionless integral scale). For this, the two-dimensional (2D) AAFs of a streamlined bridge deck in different turbulent flow fields are experimentally investigated, wherein the 2D AAF is determined by separating out the 3D effect from the 3D AAF. Consistent with the previous studies, the 3D AAFs exhibit significant flow field dependence, and are less than the Sears function in low-frequency range. Different from the 3D AAF, the 2D AAFs obtained in two turbulent flow fields are higher than the Sears function and have a good consistency in various turbulent flows. It can be therefore considered that the identification accuracy of 2D AAF of a streamlined bridge deck is not related to the dimensionless integral scale, which might avoid the possible deviation caused by the mismatch of integral scale in the wind tunnel test. An empirical formula for the 2D AAF of a streamlined bridge deck is then proposed by fitting the experimental data. In addition, to further examine the validity of above conclusion, a comparison between the 3D AAFs of a streamlined bridge deck measured in other wind tunnel tests and the predictions calculated with the present 2D AAF is also made.