角柱の振動時における3次元的空気力特性について

Abstract

The purpose of the paper is to investigate the characteristics of the unsteady aerodynamicforces acting on a three dimensional square prism which is sinusoidally oscillated across winddirection with a rocking mode.Wind tunnel experiments were conducted by use of the forced oscillation technique suggestedby Bishop and Hassan. The following results were obtained.1)The unsteady aerodynamic forces acting on an oscillating model showed the non-linear phe-nomenon with respect to the reduced wind velocity and the oscillating amplitude.2)The application of the quasi-steady theory to the galloping oscillation is thought to be di-fficult below the reduced wind velocity of 30.3)The existence of the locking-in region is observed. The region is expanded according tothe increasing wind velocity.4)The response curves related to the oscillating amplitude and the wind velocity are obtained, which are plotted with the parameters of the damping ratios.5)The experiments by the forced oscillation technique are compared with the free oscillationexperiments. The good agreements are observed with the both results.