THE EFFECT OF THE TURBULENCE INTEGRAL SCALE ON THE EXTREME WIND PRESSURES ON THE WINDWARD SURFACE OF THE CAARC MODEL AND THE CORRECTION METHOD

The turbulence profile in the atmospheric boundary can be correctly simulated, but the turbulence integration scale is difficult to accurately simulate. For the CAARC (commonwealth advisory aeronautical research council) standard high-rise building model, the actual turbulence integration scale is 1.4 to 2.7 times that of the common integral scale used in high-rise buildings in conventional wind tunnels. In this paper, five different turbulent integration scales of atmospheric boundary layer wind fields of Category B were considered. One of them was close to the actual flow field, and the effect of the turbulent integration scale on the extreme wind pressure characteristics on the windward of the CAARC model was quantitatively studied by comparing the remaining four flow fields with this flow field. The results show that the extreme wind pressure coefficient increases with the increase of the turbulence integral scale, and the error of the extreme wind pressure coefficient increases with the increase of the error of the simulated turbulence integral scale. When the actual turbulence integral scale is 3.25 times the simulated integral scale, the actual extreme wind pressure coefficient is 1.55 times the extreme wind pressure coefficient in simulated integral scale, and the error rate is as high as 35%. And the closer the stagnation point, the more significant the effect of the turbulence integral scale. To better understand the effect of the turbulence integral scale, the mechanism of the effect of the turbulence integration scale on the extreme wind pressure was analysed through the power spectrum of the fluctuating pressure. Finally, the correction formula of extreme wind pressure coefficient on windward was proposed according to the effect of turbulent integral scale on the extreme wind pressure coefficient. The turbulence integral scale used in this test covers all the error ranges simulated by the turbulence integral scale commonly used in high-rise buildings in conventional wind tunnels, and the standard high-rise building model can provide a correction basis for all wind tunnel experimental results and can be generalized to other blunt bodies.