Determination of complex aerodynamic admittance of bridge decks under deterministic gusts using the Vortex Particle Method. Issue 193 (October 2019)

• Record Type: Journal Article
• Authors: Kavrakov, Igor; Argentini, Tommaso; Omarini, Simone; Rocchi, Daniele; Morgenthal, Guido
• Is Part Of: Journal of wind engineering and industrial aerodynamics. Issue 193(2019)
• Publication Date: 2019-10
• Subjects: Aerodynamic admittance -- Computational fluid dynamics -- Vortex particle method -- Buffeting -- Long-span bridges; Wind-pressure -- Periodicals; Buildings -- Aerodynamics -- Periodicals; Pression du vent -- Périodiques; Constructions -- Aérodynamique -- Périodiques; Buildings -- Aerodynamics; Wind-pressure; Periodicals
• DOI: 10.1016/j.jweia.2019.103971
• Languages: English
• ISSNs: 0167-6105

Abstract

Abstract: The accurate description of the aerodynamic forces due to free-stream turbulence acting on a stationary bridge deck represents a challenging task. This paper presents a Computational Fluid Dynamics (CFD) approach based on the two-dimensional (2D) Vortex Particle Method (VPM) for simulation of a six-component complex aerodynamic admittance. Deterministic free-stream turbulence is simulated by modeling the wakes of two fictitious pitching airfoils with vortex particles. For out-of- or in-phase sinusoidal oscillations of the airfoils, a longitudinal or vertical sinusoidal gust is obtained along the centerline, respectively. A closed-form relation, based on an existing mathematical model, is deduced to relate the gust amplitudes and vortex particles' circulation. Positioning a section downstream of the particle release locations yields sinusoidal buffeting forces. The complex aerodynamic admittance is then determined as a transfer function between the buffeting forces and the deterministic free-stream turbulence. A verification of the method is performed for the complex Sears' admittance of a flat plate. Finally, the CFD method is validated against wind tunnel tests for a streamlined bridge deck. The results from both, verification and validation, yielded a good agreement. Applications of the presented method are foreseen in the scope of buffeting analyses of line-like structures under the strip assumption. Highlights: Aerodynamic admittance is obtained in its complex form using the Vortex Particle Method. Deterministic sinusoidal gusts are simulated by modeling the wakes of two flapping airfoils. Analytical relation is derived to relate the gust amplitude and wakes' circulation. Verification is performed against Sears function for the aerodynamic admittance of a flat plate. The method is validated with wind tunnel experiments for the aerodynamic admittance of the Third Bosporus Bridge.