CFD-based Analysis Of Wind Resistance Of Blunt Bridges’ Sections

With the continuous development of bridge construction, the bridge span islonger and longer, and elevation is higher and higher. There are more wind disasterson bridge, so wind load has been one of the control loads in the design of modernbridge. In the wind resistance of bridge, the three component coefficients are keyparameters in the bridge wind-resisted design. Nowadays, wind tunnel test is still themost fundamental way to evaluate the aerodynamic stability, which requires long testperiod，high cost，and complex, and the flow visualization in the wind tunnel is verydifficult. The development of computational fluid dynamics provides a possibleeffective mean to study the wind-resistance of bridge in stead of wind tunnel test, thisis numerical simulation. In the short term, due to the limitation of objective conditions,CFD can′t replace the wind tunnel investigations, but now it can replace wind tunneltest to provide parameters and theoretical analysis method for research, it also turnsout to be useful to study the various wind effects on long-span bridges.In the first, we talked about basic knowledge of fluent, such as the equations offluid mechanics、commonly used theories of finite differences and the basic principles.Based on a rectangular cross, we use standard k-ε and SST two equation turbulentmodels to simulate three component coefficients of girder section under differentattack angle. Extraction calculated results and test values are compared to show thepressure distribution and velocity distribution around the sections. The results showthat numerical simulated by using SST turbulent model fits well with wind tunnel testresults, at the same time we verified CFD can accurate three component coefficientsof girder section comparatively and display fluid flow superiority.For further study on precision of three component coefficients on bluff sectionwe also research the three component coefficients on flat rectangular cross andcompares with wind tunnel test results to further prove precision of using SSTturbulent model. We find the different streamlined degree of separated box girders hasan influence on aerodynamic coefficients. Based on Malinghe Bridge, we computeother bluff sections to provide the basic reference for the wind resistance coefficient.