Numerical Simulation on Aerodynamic Characteristics of Split Three-box Girder
To investigate the aerodynamic characteristics of split three-box girder,based on the split three-box girder of a highway-railway cable-stayed suspension cooperative system bridge,the 2D numerical simulation on aerodynamic characteristics of split three-box girder with different gap to height ratios(G/D)and different wind attack angles is carried out by using FLUENT software.The described aerodynamic characteristics of main girder mainly include the aerodynamic force coefficients,vorticity magnitude field,mean pressure coefficient distributions,and distributions of standard deviation of pressure coefficient.The numerical simulation result indicates that within the studied parameters and with different wind attack angles,the drag force coefficients increase with the increment of G/D.The lift force coefficients and moment coefficients do not change monotonously with G/D.The moment coefficients are more sensitive to the change of G/D.With different G/Ds,the slopes of lift force coefficients with wind attack angle are all positive,indicating that the flutter performance of split three-box girder is good.At 0° wind attack angle,there is only periodic vortex shedding in the wake of deck when G/D=0.When G/D=1.61,the vortex shedding at gap regions of deck and at the surfaces of middle box,and the downstream box is significant at 0° wind attack angle.Compared with 0° wind attack angle,the vortex shedding at gap region of middle box and downstream box and at the surface of downstream box is weakened at±10° wind attack angles.The existence of deck gaps increases the magnitude of negative mean pressure coefficient on the top surface of middle box,leading to the increment of standard deviation of pressure coefficient of deck.When G/D=1.61,compared with 0° wind attack angle,the pressure fluctuation on deck surface at±10° wind attack angles is weakened,especially the standard deviation of pressure coefficient of downstream box is significantly reduced.The critical G/D of split three-box deck is 2.08.
bridge engineeringaerodynamic characteristicsnumerical simulationsplit three-box girdergap to height ratio
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