Abstract
To investigate fluctuating wind forces induced by seperating and reattaching flow, pressures on the side surface of a two-dimensional model having a rectangular section of the ratio 1 : 7.5 are measured. Distributions of static pressures and rms values of fluctuation made by turbulent flow are different from those of smooth flow. It is found that the turbulence in the general flow make the seperating flow more turbulent and unstable. However, correlations are not different in the both cases of turbulent and smooth flows, and roughly similar to the cace of the wall pressure bneath the turbulent boundary layer. The fluctuations of pressure accompanying reattaching flow are less correlated and more negatively correlated in the space along the flow direction than the those of the wall pressure without reattaching flow. Spatial correlations are integrated over limited areas near the center of side surface. The result shows that the rms force coefficients on the areas d×d and 2d×2d are 0.65 and 0.45 times of the rms pressure coefficient respectively. (d; charactaristic length of the model).
