Experimental Study of Impact Angle of Microburst Effects on a Cubic Structure – Part A: Stationary Microburst Observation

Document Type : Research Article

Authors

1 Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran

2 Department of civil engineering, Najafabad branch, Islamic Azad University, Najafabad, Iran

3 Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran

Abstract

A Downburst can produce divergent outflow wind on the ground surface, which is different from the behavior of atmospheric boundary layer flows. In this research, the effects of downburst on a cube-shaped structure in two different directions of flow (α), four different ground surface angels relative to the downburst direction (θ), and different radial distances (X/D) relative to the downdraft center were investigated by a simulator that was made for this thunderstorm. Simulation of this flow is created by a blower whose task is to uniformize the flow created by the fan embedded behind it. The velocity and turbulence intensity of flow was measured at different X/Ds. also, the distribution of pressure coefficient on the sides of the model was measured at the X/D locations. In addition, a good agreement has been observed between the data comparison of this study and previous studies. It was observed that at the center of the downburst for all θs, the structure has a positive pressure coefficient along its sides. By moving away from the center of the storm, the flow behavior is similar to the boundary layer flows. By increasing θ, it was found that the difference of pressure coefficient between the windward side relative to the roof and the backward sides, increased, which in the worst case has changed by about 80%. By examining the direction of flow to the model, it was found that the force coefficients when the model is at α=45°, are about 35% less than when the model is at α=0°. Finally, it was found that at X/D=1, the maximum force coefficient is applied to the structure.

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Main Subjects

References

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Amirkabir Journal of Mechanical Engineering
Volume 54, Issue 5
August 2022
Pages 961-984

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