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实测强风工况下高度167 m的徐州彭城电厂冷却塔的表面风荷载,并归纳历史上其他研究人员给出的实测结果,以丰富高超临界雷诺数(Re)区间二维圆柱绕流的试验成果.在低湍流度均匀流场和高湍流度大气边界层流场中分别开展4种风速8类粗糙度条件下的冷却塔刚性模型测压风洞试验,通过对比低雷诺数(Re=2.11054.19105)条件下的风洞试验结果和高雷诺数(Re=5.41071108)条件下的现场实测结果研究各种静动态绕流特征随雷诺数的变化规律,重点考察雷诺数无关现象的产生条件.研究结果表明,对于物表相对粗糙度在0.01以上的圆柱绕流,雷诺数不相关现象存在于很宽的雷诺数范围(2105Re1108)内;增大来流湍流度亦能引起的雷诺数无关现象,但此时该现象可能仅存在于一个较窄的低雷诺数范围内.Flow around a circular cylinder is a classic scenario which invariably draws the attention of the fluid mechanics circle, because its relevant studies are of both theoretical and practical significances. However, most experiments are conducted below transcritical Reynolds number(Re) regime(Re3.5106) due to the limitations of the wind tunnel modeling technique, which makes the obtained results inapplicable to some full-scale conditions. To this end, the field measurements for wind-induced pressures on a 167-meter high large cooling tower are conducted at Re=6.59107 to enrich the experimental results of flow past a circular cylinder in transcritical Re regime. Besides, the wind effects at low Re(Re=2.1105-4.19105) are also obtained by tests on a 1:200 rigid cooling tower model in a wind tunnel with considering 4 types of wind speeds, 8 types of surface roughness, and 2 flow fields. Employing the data obtained from both field measurements and wind tunnel model tests, the variations of static/dynamic flow characteristics with Re increasing are studied. It is found that 1) with the increase of Re, the drag coefficient for the smooth-walled tower in the uniform flow field decreases dramatically in the critical Re regime and increases slowly in the supercritical regime, which accord with Roshko's and Achenbach's results; 2) for smooth-walled tower, both the base pressure coefficient and pressure coefficient increase significantly with the increase of Re in critical and supercritical regimes, which qualitatively accord with Shih's results; and 3) the finding of the Strouhal number is supportive to Shih's result(i.e., shedding from the rough cylinder persists throughout the Re range tested). More importantly, special attention is paid to the Re-independence phenomenon of fluid flow, which is a typical phenomenon occurring in transcritical Re regime. Results indicate that the Re-independence exists in an Re range from 2105 to 1108 for a circular cylinder with a relative roughness greater than 0.01, and the increased free-stream turbulence can also induce Re-independence which probably exists in a narrow low Re range. Considering the flow mechanism, a reasonable explanation can be found for the Re-independence phenomenon, i.e., the critical and supercritical regimes narrow and move to lower Re range with the increase of surface roughness or the increase of free-stream turbulence, so Re independence can occur at a very low Re.
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Keywords:
- flow past a circular cylinder /
- transcritical Reynolds number regime /
- field measurement /
- Reynolds number independence
[1] Roshko A 1961 J. Fluid Mech. 10 345
[2] Achenbach E 1968 J. Fluid Mech. 34 625
[3] Dragoiescu C, Xie J, Kelly D 2011 13th International Conference on Wind Engineering Amsterdam, Netherlands, July 11-15, 2011 p1023
[4] Matsuda K, Cooper D R, Tanaka H, Tokushige M, Iwasaki T 2001 J. Wind Eng. Ind. Aerodyn. 89 619
[5] Niemann H J 1971 Zur Stationären Windbelastung Rotations-symmetrischer Bauwerke Im Bereich Transkritischer Reynoldszahlen Techn.-wiss. Mitt. Nr. 71-2, Inst. fr Konstr. Ingenieurbau, Ruhr-Universität Bochum, West Germany(in German)
[6] Sollenberger N J, Scanlan R H 1974 Proceedings of the Symposium on Full-scale Measurements of Wind Effects University of Western Ontario, Canada, February 2-5, p79
[7] Sun T F, Zhou L M 1983 J. Wind Eng. Ind. Aerodyn. 14 181
[8] Ruscheweyh H 1975 J. Wind Eng. Ind. Aerodyn. 1 335
[9] Pirner M 1982 J. Wind Eng. Ind. Aerodyn. 10 343
[10] Niemann H J, Propper H 1975 976 J. Ind. Aerodyn. 1 349
[11] Shih W C L, Wang C, Coles D, Roshko A 1993 J. Wind Eng. Ind. Aerodyn. 49 351
[12] Simiu E, Scanlan R H 1996 Wind Effects on Structures-Fundamentals and Applications to Design, Third Edition (New York:John Wiley & Sons, INC) p406
[13] Cheng X X, Zhao L, Ge Y J, Ke S T, Liu X P 2015 Adv. Struct. Eng. 18 201
[14] Liu X P 2013 M. S. Dissertation (Shanghai, China:Tongji University)(in Chinese)[刘晓鹏2013硕士学位论文(上海:同济大学)]
[15] Gu Z F, Sun T F, He D X, Zhang L L 1992 Acta Mech. Sin. 24 522(in Chinese)[顾志福, 孙天风, 贺德馨, 张亮亮1992力学学报24 522]
[16] Achenbach E 1971 J. Fluid Mech. 46 321
[17] Schewe G 1983 J. Fluid Mech. 133 265
[18] Niemann H J, Hölscher N 1990 J. Wind Eng. Ind. Aerodyn. 33 197
[19] Farell C 1981 J. Eng. Mech. ASCE 107 565
[20] Basu R I 1986 J. Wind Eng. Ind. Aerodyn. 24 33
[21] Bearman P W 1968 The Flow around a Circular Cylinder in the Critical Reynolds Number Regime NPL Aero Report 1257
[22] Kiya M, Suzuki Y, Arie M, Hagino M 1982 J. Fluid Mech. 115 151
[23] Cheung J C K, Melbourne W H 1983 J. Wind Eng. Ind. Aerodyn. 14 399
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[1] Roshko A 1961 J. Fluid Mech. 10 345
[2] Achenbach E 1968 J. Fluid Mech. 34 625
[3] Dragoiescu C, Xie J, Kelly D 2011 13th International Conference on Wind Engineering Amsterdam, Netherlands, July 11-15, 2011 p1023
[4] Matsuda K, Cooper D R, Tanaka H, Tokushige M, Iwasaki T 2001 J. Wind Eng. Ind. Aerodyn. 89 619
[5] Niemann H J 1971 Zur Stationären Windbelastung Rotations-symmetrischer Bauwerke Im Bereich Transkritischer Reynoldszahlen Techn.-wiss. Mitt. Nr. 71-2, Inst. fr Konstr. Ingenieurbau, Ruhr-Universität Bochum, West Germany(in German)
[6] Sollenberger N J, Scanlan R H 1974 Proceedings of the Symposium on Full-scale Measurements of Wind Effects University of Western Ontario, Canada, February 2-5, p79
[7] Sun T F, Zhou L M 1983 J. Wind Eng. Ind. Aerodyn. 14 181
[8] Ruscheweyh H 1975 J. Wind Eng. Ind. Aerodyn. 1 335
[9] Pirner M 1982 J. Wind Eng. Ind. Aerodyn. 10 343
[10] Niemann H J, Propper H 1975 976 J. Ind. Aerodyn. 1 349
[11] Shih W C L, Wang C, Coles D, Roshko A 1993 J. Wind Eng. Ind. Aerodyn. 49 351
[12] Simiu E, Scanlan R H 1996 Wind Effects on Structures-Fundamentals and Applications to Design, Third Edition (New York:John Wiley & Sons, INC) p406
[13] Cheng X X, Zhao L, Ge Y J, Ke S T, Liu X P 2015 Adv. Struct. Eng. 18 201
[14] Liu X P 2013 M. S. Dissertation (Shanghai, China:Tongji University)(in Chinese)[刘晓鹏2013硕士学位论文(上海:同济大学)]
[15] Gu Z F, Sun T F, He D X, Zhang L L 1992 Acta Mech. Sin. 24 522(in Chinese)[顾志福, 孙天风, 贺德馨, 张亮亮1992力学学报24 522]
[16] Achenbach E 1971 J. Fluid Mech. 46 321
[17] Schewe G 1983 J. Fluid Mech. 133 265
[18] Niemann H J, Hölscher N 1990 J. Wind Eng. Ind. Aerodyn. 33 197
[19] Farell C 1981 J. Eng. Mech. ASCE 107 565
[20] Basu R I 1986 J. Wind Eng. Ind. Aerodyn. 24 33
[21] Bearman P W 1968 The Flow around a Circular Cylinder in the Critical Reynolds Number Regime NPL Aero Report 1257
[22] Kiya M, Suzuki Y, Arie M, Hagino M 1982 J. Fluid Mech. 115 151
[23] Cheung J C K, Melbourne W H 1983 J. Wind Eng. Ind. Aerodyn. 14 399
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