Trial production of a new wind tunnel to simulate fluctuations in velocity and direction of natural wind

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The present project has been conducted to develop a new wind tunnel system to simulate fluctuations in velocity and direction of natural wind. The system consists of two wind blowers of which directions are inclined to each other in the horizontal plain at the angle of 45 degree. The fan of each blower is driven by an AC servomotor which is operated by computer-generated voltage histories. Two wind streams from these two blowers are merged to each other in order to generate a single stream of specified direction and velocity The main results of the present work are listed below.(1) When two steady flows are merged, the resulting wind stream is sufficiently smooth.(2) We have established a mathematical function between the two wind velocities and the objective velocity and direction of the resulting wind stream.(3) Using this function, we have succeeded to generate large motion of unsteady wind streams both in wind velocity and direction.(4) Using this wind tunnel system, we have succeeded to generate wind streams which possess the velocity fluctuation in obedience with the power spectrum of natural wind, not only in the direction of the flow but also in the perpendicular direction to the flow.