Measurement of unsteady aerodynamic force to evaluate large-amplitude oscillation of four-bundled conductors

Abstract

In this study, measurement tests were performed using rotary devices with arbitrary input waveforms to investigate the unsteady aerodynamic force characteristics of four-bundled conductors. Aerodynamic coefficients, which are defined as functions of the angle of attack and non-dimensional angular velocity, were measured from tests performed at a constant angular velocity. Subsequently, the validity of the aerodynamic force formulation using these two variables was confirmed by comparing the unsteady aerodynamic coefficients obtained from two different measurement tests: one performed at constant angular velocity, and the other that used sinusoidal waves as the input. Furthermore, results of the time history analysis, in which the aerodynamic forces were calculated by using the relative angle of attack and relative angular velocity at each time step, showed good agreement with the test results for large-amplitude galloping.