Wind borne debris

[47] DEVELOPMENT OF THE ESTIMATION METHOD FOR THR ADHESION OF AIRBORNE SALT ONTO A BODY BY MEANS OF THE WIND TUNNEL EXPERIMENT

○Hiroshi Hasebe¹, Ryohei Sone¹, Youhei Haruki¹, Takashi Nomura¹ (1.Nihon university, College of Science and Technology, Department of Civil Engineering)

Keywords:Airborne salt, Mist flow, Ion electrode method, Bridge girder

Galloping phenomena occasionally affect overhead transmission lines under ice and snow accretion. To clarify the basic dynamic response characteristics of the vertical, horizontal, and torsional three-degree-of-freedom (3DOF) galloping of four-bundled conductors, time-history analyses were conducted for systems with varied DOF and natural frequency ratios. In the vertical 1DOF system, the range of angle of attack which enlarges the oscillation was identified by analyzing the work performed by aerodynamic force. Then, by considering the energy balance in one oscillation period, the stable and unstable limit-cycle amplitudes were clarified. Finally, the essential oscillation types in 3DOF systems were categorized according to the mean torsional angle as vertical–horizontal 2DOF coupling oscillation, vertical–torsional 2DOF coupling oscillation, and vertical 1DOF oscillation.