Transformation of wind tunnel data on aeolian vibrations for application to random conductor vibrations in a turbulent wind

Abstract

Measurements were made recently in a wind tunnel to determine the logarithmic decrements of the aeolian excitation of a flexible conductor model over a wide range of wind velocities and vibration amplitudes. It is shown here how these data can be transformed numerically to take into account the turbulence of real wind and the random nature of aeolian vibrations.The principal results are presented as a family of curves giving the normalized logarithmic decrement 6r (or normalized excitation factor qr = 6r/n) of aeolian excitation as a function of the normalized root-meansquare (rms) value of the transverse displacements of the conductor at the virtual antinodes, with the intensity of turbulence as a parameter. These curves can be used to predict the rms values of aeolian vibrations of conductors with known internal-loss factors, at sites having a known intensity of turbulence. The experimental results for aeolian vibrations of a conductor span in a real wind are superimposed on the family of curves obtained and show reasonable agreqment.