Experimental And Numerical Study Of Wind Pressures On 5:1 Rectangular Cylinder In Grid-Generated Turbulent Flow

With the development of computational fluid dynamics method,three-dimensional numerical simulation methods are extensively used in the field of structural wind engineering.Because of its simple geometric characteristics,complex flow characteristics and widely practical application,5: 1 rectangular cylinder has become a research hotspot in wind engineering.But the previous numerical studies paid more attention to the aerodynamic characteristics of rectangular cylinder subjected smooth flow.In this paper,the large eddy simulation method is used to study the aerodynamic characteristics of a 5:1 rectangular cylinder in a uniform isotropic turbulence field,and the results are compared with the wind tunnel test results.The main work of this thesis is as follows:1.The wind tunnel pressure tests of a 5: 1 rectangular cylinder were conducted.The characteristics of turbulence field generated by grids with the size of 330 mm and the width of 70 mm are analyzed.In addition,the aerodynamic force characteristics such as fluctuating wind pressure coefficient,power spectral density of fluctuating wind pressure and the spanwise correlation of buffeting forces on 5: 1 rectangular cylinder model in turbulence field were studied.2.The passive simulation method was used to establish the grid at the entrance of the computational domain to generate uniform isotropic turbulence.The longitudinal development laws of turbulence under different grid sizes of computational domain were compared,and the numerical turbulence field characteristics,including turbulence intensity,integral scale,power spectral density and spatial correlation,were obtained.Then,they were compared with the turbulence field of wind tunnel test.Finally,the parameter settings of simulated turbulence field consistent with the turbulence characteristics of actual wind tunnel were determined.3.In the simulated turbulence field,the surface wind pressure characteristics of 5: 1rectangular cylinder were studied,and the buffeting lift and drag force of 5: 1 rectangular cylinder obtained by numerical simulation in this paper were compared with the results of wind tunnel test.The turbulence generated by the passive grid simulation method in this paper can better meet the uniform isotropic properties and spatial correlation.Additionally,the numerical results show that the passive simulation technique can be used to study the surface aerodynamic force characteristics of the blunt body immersed in the turbulence field.It can be used as an effective supplement method to study the unsteady aerodynamic characteristics and the spatial correlation of aerodynamic forces on rectangular blunt body sections in the turbulence field in addition to the wind tunnel test.