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Through numerical simulation investigation, a twin-winglet system is used as an aerodynamic affiliated facility to increase the flutter stability of a box-girder suspension bridge. Its flutter suppression effect can be greatly enhanced when the winglet rotation is feedback-controlled in real-time, depending on the deck motion. Since the control algorithm was previously examined by a self-consistent mathematical model, the control process is realized through computational fluid dynamics simulation in this paper to check the applicability of the device. Moreover, the non-interference assumption used in the control algorithm is analyzed carefully, with several cases of different distance between a deck and winglets. The results verify the effectiveness and robustness of the control algorithm, and also provide a quantitative conclusion about the influence effect, which can be used in the design of a twin-winglet system. In addition, the advantages of this twin-winglet facility are revealed by investigations of the flutter control mechanism. [ABSTRACT FROM AUTHOR]

Abstract: The aerodynamic behavior of a streamlined box section model is characterized in an actively controlled wind tunnel with multiple fans and vibrating airfoils in Miyazaki University, Japan. A series of single pseudo harmonic fluctuating wind flows with discrete frequencies are generated. The aerodynamic admittance components obtained via a cross-spectral identification method for different incoming flows present obvious deviations between each other. This indicates the probable dependence of aerodynamic admittance on the characteristics of oncoming flow, which implies the limitation of conventional buffeting theory. More attention is focused on the relationship between aerodynamic forces and wind turbulence components, along- and across-wind cross-wind, in pseudo sinusoidal flow conditions. It is found that the across-wind turbulence has dominant influences on lift and pitching moment forces. With the strengthening of along-wind turbulence, the lift force increases, while the drag and pitching moment forces vary with different trends in different frequency ranges. Moreover, the contribution of along-wind turbulence to lift and pitching moment forces is considered to be negligible compared with that of the cross-wind turbulence, while for the drag force, the two turbulence components present comparative contributions. [Copyright &y& Elsevier]