This paper describes a new actively controlled multi-fan wind tunnel that generates\nnatural wind as a type of turbulence wind tunnel at a reduced cost.\nThe driving section of the wind tunnel has 100 PC cooling fans that are controlled\nby an original embedded system. The fluctuating velocity wind is successfully\ngenerated with a mean velocity of 7 m/s and two turbulent intensities\nof 2% and 3% based on Karmanâ??s power spectrum density function. The\ncase of 2% has the integral scales of 5 m, 10m and 20 m, and the case of 3%\nhas the integral scales of 3 m, 6 m and 15 m with a turbulence grid. In particular,\nthe wind with the turbulent intensity of 2% satisfies the Kolmogorovâ??s\n-5/3 multiplication rule of inertial subrange with the frequency range from\n0.01 Hz to 2.0 Hz. Consequently, the new wind tunnel can be used for studying\nengineering technology and research regarding conditions with natural\nwind.
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