Aerodynamic admittance of truss girder in homogenous turbulence

2-wavenumber lift admittance of equivalent truss cross-section reveals energy transferring trend of this structure: gathering turbulence energy mainly to a relative low wavenumber scope. 2-dimensional admittance is larger than 3-dimensional admittance at reduced frequency range from 0.03∼0.6, which might cause imprecise buffeting response calculation. 3-dimensional segmental admittance is in parallel lower that cross-sectional admittance, most possibly due to aerodynamic force redistribution on truss segment. Span-wise coherence and correlation coefficient of equivalent cross-section are obtained and observed a little smaller than that of segment, which is reasonable, for truss girder has already “averaged” cross-sectional correlation. The result proved buffeting force's correlation is larger than turbulence's once again. (a) 2-wavenumber lift admittance of equivalent cross-section. (b) Comparison of 3 dimensional segmental admittance, 2-dimensional and 3-dimensional cross-sectional admittance and Sears function. (c) Span-wise coherence of equivalent cross-section under different intervals. (d) Span-wise correlation of equivalent cross-section and its comparison with segmental and turbulence correlation.178