A Numerical-Experimental Framework to Separate the Effects of Different Turbulence Components on the Buffeting Forces of Bluff-body Structures

Abstract

In conventional buffeting analyses of flexible civil engineering structures, the differences between the effects of longitudinal (u-) and vertical (w-) turbulence components were usually ignored. This assumption could cause unpredictable errors and needs to be refined. To improve the accuracy of buffeting analyses, this paper proposes a framework combining Computational Fluid Dynamics simulation and wind tunnel test to analyze the buffeting forces considering the differences between turbulence components. First, the Aerodynamic Admittance Functions (AAFs) with respect to u- and w- turbulence are numerically evaluated. Next, the total buffeting forces are experimentally measured. Finally, the numerical and experimental results are combined following a theoretical scheme to separate the effects of u- and w-turbulence. Results show that u- and w- turbulence have different contributions to the buffeting forces, directly indicating the inaccuracy of the conventional assumption. In the turbulence field investigated, the buffeting lift force at zero angle of attack (AoA) are all contributed from the w-turbulence, while the contribution from u-turbulence increase as AoA increases. This numerical-experimental framework overcomes the limitations of the conventional method by quantitatively describing the different contributions of u- and w- turbulence.