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Structural Engineering and Mechanics Volume 66, Number 2, April25 2018, pages 273-283 DOI: http://dx.doi.org/10.12989/sem.2018.66.2.273 |
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Multi-dimensional wind vibration coefficients under suction for ultra-large cooling towers considering ventilation rates of louvers |
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S.T. Ke, L.Y. Du, Y.J. Ge and Y. Tamura
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| Abstract | ||
| Currently, the dynamic amplification effect of suction is described using the wind vibration coefficient (WVC) of external loads. In other words, it is proposed that the fluctuating characteristics of suction are equivalent to external loads. This is, however, not generally valid. Meanwhile, the effects of the ventilation rate of louver on suction and its WV are considered. To systematically analyze the effects of the ventilation rate of louver on the multi-dimensional WVC of ultra-large cooling towers under suctions, the 210 m ultra-large cooling tower under construction was studied. First, simultaneous rigid pressure measurement wind tunnel tests were executed to obtain the time history of fluctuating wind loads on the external surface and the internal surface of the cooling tower at different ventilation rates (0%, 15%, 30%, and 100%). Based on that, the average values and distributions of fluctuating wind pressures on external and internal surfaces were obtained and compared with each other; a tower/pillar/circular foundation integrated simulation model was developed using the finite element method and complete transient time domain dynamics of external loads and four different suctions of this cooling tower were calculated. Moreover, 1D, 2D, and 3D distributions of WVCs under external loads and suctions at different ventilation rates were obtained and compared with each other. The WVCs of the cooling tower corresponding to four typical response targets (i.e., radial displacement, meridional force, Von Mises stress, and circumferential bending moment) were discussed. Value determination and 2D evaluation of the WVCs of external loads and suctions of this large cooling tower at different ventilation rates were proposed. This study provides references to precise prediction and value determination of WVC of ultra-large cooling towers. | ||
| Key Words | ||
| ultra-large cooling tower; wind tunnel test; ventilation rate; suction; external load; wind vibration coefficient | ||
| Address | ||
| S.T. Ke: 1) Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Road, Nanjing 210016, China 2) State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China L.Y. Du: Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Road, Nanjing 210016, China Y.J. Ge: State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China Y. Tamura: Center of Wind Engineering Research, Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa 243-0297, Japan | ||