Analysis of Aerodynamic Load Effect on Thin Plat Section in Multiple Fan Active Control Wind Tunnel

Abstract

In atmospheric boundary, the power spectral density of turbulent wind simulated passively by the grid layer is regulated difficultly with the problem of smaller integral length of turbulence. For the advantage of active control method in adjusting the power spectral density and the integral length more simply, 11×9 multiple fan active control wind tunnel in Miyazaki University is utilized to debug many kinds of harmonic turbulent wind. Three-component aerodynamic forces on thin plat section (aspect ratio 22.5:1) in the harmonic turbulent wind field were measured by using the high frequency force balance of better stability and precision with testing the turbulent wind synchronously. The load effects on the model under different conditions, such as mean wind velocity, fluctuation frequency, turbulence intensity and integral length, were compared and analyzed. Frequency doubling amplification effect caused by the fixed wall boundary reflection effect in atmospheric boundary physical wind tunnel was reported and confirmed. In the validated effective frequency range where discrete frequency load effect caused by sinusoidal turbulent wind can be linearly superposed, the impacts on aerodynamic load effect induced by turbulence integral length and turbulence intensity were analyzed preliminarily. The differences between the conventional buffeting force theory and the wind tunnel test results of typical section model were clarified.