Wind Tunnel Investigation on Wind Load Characteristics of Triangular Guyed Mast

Abstract

Two models of triangular guyed mast were tested by high frequency force balance (HFFB) technique under uniform and turbulent flow with different turbulent intensities, respectively. The mean and RMS force coefficients and the force spectra in along-wind, across-wind and torsion direction were obtained from wind tunnel test. Some existing codes and standards for the mean drag coefficients for guyed mast and ancillaries were employed and compared with test results, with emphasis on the influence of Reynolds number, turbulent intensity, wind incidence angle and ancillaries on wind force coefficients. The force spectra in along-wind direction are similar to the spectra of fluctuating wind velocity, while the force spectra in across-wind and torsion direction consist of the wind turbulence spectra in low frequency range and vortex shedding spectra in high frequency range. The vortex shedding spectra of the guyed mast without ancillaries have one peak, and the reduced frequency of the peak is close to 1.8. When the attack angle reaches 90°, the vortex shedding spectra of the guyed mast with ancillaries have two distinct peaks with the reduced peak frequencies closed to 0.9 and 2.2, respectively. The characteristics of the vortex shedding spectra for lattice mast and the influence mechanism of the ancillaries were discussed.

Keywords: guyed mast,  high frequency force balance,  wind tunnel tests,  wind load characteristics