The Identification Of Flutter Derivatives For Long-span Bridges Based On FLUENT

With the immense leap in computational speeds in the recent past, numerical experiments via Computational Fluid Dynamics are fast maturing as a viable complement, if not an alternative to wind tunnel investigations to study the various wind effects on bridges.Based on FLUENT, the dynamic mesh technology of CFD is used to identify 2-D segmental model's eight flutter derivatives through calculation of its self-excited forces. The present study focuses mainly on two sections:1. The forced oscillating procedure is used to compute flutter derivatives of the ideal flat plate, and comparing the results of the ideal flat plate with the Theodorsen's theoretic solutions.2. The forced oscillating procedure is employed to compute flutter derivatives and onset wind speeds for flutter of the bridge in Ningbo, and comparing the results with wind tunnel test.The analytical results obtained using the methodology which were found to match reasonably well with those obtained in the wind tunnel test. The method is therefore considered reliable and can be used as a reference for other bridges.Comparing the present numerical approaches with wind tunnel tests, it is shown that the present study don't require expensive wind tunnels and costly equipments, also needn't prepare the scaled testing models, while casting off measurement difficulties and higher operating costs. Apparently, it is easy and economical to investigate aerodynamic characteristics of various proposed section models and determine aerodynamic parameters. Meanwhile, Numerical simulations can capture the constants included in the aerodynamic derivatives with better accuracy. Therefore, a combination of numerical approaches with wind tunnel tests will makes it possible to successfully evaluate the flutter stability of bridges girder cross-section.