Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/15574
標題: 振盪來流下二維矩柱氣動力效應之數值探討
Numerical Investigations of Aerodynamic Force on Rectangular Cylinders in Oscillating Approaching Flow
作者: 鍾政洋
Chung, Cheng-Yang
關鍵字: Numerical simulation;數值模擬;Oscillating approaching flow;Rectangular cylinder;Morison equation;振盪來流;矩柱;莫瑞森方程式
出版社: 土木工程學系所
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(2001), “Dynamic Responses of a Suspension Bridge with a Rectangular Cross-section,” Proceedings of the Fifth Asia-Pacific Symposium on Wind Engineering, Kyoto, Japan, pp.397-400. [7] Fang, F. M., Li Y. C., Chen C. C. and Liang, C. C. (2005), “Numerical Predictions on the Dynamic Response of a Suspension Bridge with a Trapezoidal Cross-Section,” Journal of the Chinese Institute of Engineers, 28, 2, pp. 281-291. [8] Han, T. (1989), “ Computational Analysis of Three-Dimensional Turbulent Flow around a Bluff Body in Ground Proximity ,” AIAA J. Vol.27, No.9, pp.1231-1219. [9] Hanson, T., Summers, D. M. and Wilson, C. B. (1984), “Numerical Modelling of Wind Flow Over Buildings in Two Dimensions ,” Int’l J. Numerical Methods in Fluids, Vol.4, pp.25-41. [10] Honji, H. (1981) “Streaked flow around an oscillating circular cylinder” J. Fluid Mech.,Vol107, pp.509-520 [11] Lam, K. M. and Dai, G. Q. (2002), “Formation of vortex street and vortex pair from a circular cylinder oscillating in water” Experimental Thermal and Fluid Science, Vol. 26, pp.901-915 [12] Lane, J. C. and Loehrke, R. I. (1980), “ Leading Edge Separation from a Blunt Plate at Low Reynolds Number ,” J. Fluids Engg., Trans. ASME, Vol.102, pp.495-496. [13] Lu, X.Y. (2003), “ Three-Dimensional Instability of an Oscillating Viscous Flow past a Circular Cylinder ,” Applied Mathematics and Mechanics, Vol.24, pp.791-800. [14] Mathews, E. H. (1987), “ Prediction of the Wind-Generated Pressure Distribution Around Buildings ,” J. Wind Engg. and Ind. Aerod., Vol.25, pp.219-228. [15] Mizota T., Yamada H., Kubo Y., Okajima A., Knisely C.W. and Shirato H., “Aerodynamic characteristics of fundamental structures”, Part 1, Section 2, J. Wind Engrg., 36(1988), 50-52. [in Japanese] [16] Moffatt, H.K. (1961) “Viscous and resistive eddies near a sharp corner” Computer Methods in Applied Mechanics and Engineering, Vol.18, pp.1-18 [17] Morison, J. R., et al. (1950) “The Force Exerted by Surface Waves on Plies” Petroleum Transactions, Vol.189, pp.149-157 [18] Murakami, S. and Mochida, A. (1988), “ 3-D Numerical Simulation of Airflow around a Cubic Model by Means of the K-ε Model ,” J. Wind Engg. and Ind. Aerod., Vol.31, pp.283-303. [19] Murakami, S., Mochida, A. and Hayashi, Y. (1990), “ Examining the K-ε Model by Means of A Wind Tunnel Test and Large-Eddy Simulation of the Turbulence Structure Around A Cube ,” J. Wind Engg. and Ind. Aerod., Vol.35, pp.87-100. [20] Murakami, S., Mochida, A. and Hayashi, Y. (1995), “ On Turbulent Vortex Shedding Flow Past 2D Square Cylinder Predicted by CFD ,” J. Wind Engg. and Ind. Aerod., Vol.54/55, pp.191-211. [21] Okajima A., “Strouhal numbers of rectangular cylinders”, J. Fluid Mech., 123(1982), 379-398. [22] Okajima, A. (1982) “Numerical Simulation of Flow Around Rectangular Cylinders” J. Fluid Mech., Vol.123, pp.379-398 [23] Okajima, A. (1990) “Numerical Simulation of Laminar and Turbulent Flow Around Rectangular Cylinders” International Journal for Numerical Methods in Fluids, Vol33, pp.171-180 [24] Okajima, A. and Sakai, H (1992) “Numerical Simulation of Flow Rectangular Cylinders” J. Fluid Mech., Vol.15, pp.999-1012 [25] Okajima, A., Matsumoto, T. and Kimura, S. (1998), “Force measurements and flow visualization of circular and square cylinders on oscillatory flow” JSME Int J, Vol. 41,.pp.796-805. [26] Pocha J.J.( 1971), “On unsteady flow past cylinders of square cross-section”, Ph.D. Thesis, Department of Aeronautics, Queen Mary College, London. [27] Sarpkaya, T. (1986) “Force on a circular cylinder in viscous oscillatory flow at low Keulegan-Carpenter numbers” J. Fluid Mech., Vol.165, pp.61-71 [28] Song, C.C.S. & Yuan, M. (1988) , “A weakly compressible flow model and rapid convergence methods. Journal of Fluids Engineering, 110, 4, pp.441-455. [29] Takashi, N., Suzuki, Y., Uemura, M. and Kobayashi, N.(2003) “Aerodynamic force on a square cylinder in oscillating flow with mean velocity” J. Wind Engg. And Ind. Aerod., Vol.91, pp.199-208 [30] Williamson, C. H. K. (1985) “Sinusoidal flow relative to circular cylinders” J. Fluid Mech., Vol.155, pp.141-174 [31] Williamson, C. H. K. and Roshko, A. (1988) “Vortex formation in the wake of oscillating cylinder” J. Fluid Mech., Vol.2, pp.355-381 [32] Zheng, W. and Dalton, C. (1999) ”Numerical prediction of force on rectangular cylinders in oscillating viscous flow” J. Fluid Mech., Vol.13, pp.225-249 [33] 蔡惠文 (1996) “均勻來流中二維矩柱之流場模擬”中興大學土木研究所碩士論文
摘要: 
本研究以數值計算方法,模擬二維矩柱在平均流速不為零之週期性振盪來流下之矩柱受力行為。在高雷諾數的情況下,改變週期性振盪來流之速度振幅比(AR)自0.1至0.7、庫立根卡本特數 (KC) 自0.5至16,以及矩柱深寬比(B/D)由1至4,目的在探討改變之參數對二維矩柱受力行為之影響。
為了正確地反應出流場中既有之非恆定性與紊流特性,研究中之流場模擬採用微可壓縮流法與次網格紊流模型。數值計算之結果以莫瑞森方程式為根據,運用最小平方法迴歸出相應之阻力係數(Cd)、升力係數(Cl),以及矩柱受非線性振動力產生的慣性項阻力係數(Cd~)、慣性項升力係數(Cl~)。
研究中發現,本數值模式對於振盪來流下矩柱之阻力變化預測頗為良好。在零攻角的振盪來流中,莫瑞森方程式無法正確地描述矩柱升力的時間變化,但對於柱體阻力變化之預測頗佳。此外,當來流之無因次振盪週期與矩柱之渦散週期相當時會出現共振反應,引致最大阻力係數之發生。

The unsteady forces on rectangular cylinders selected aspect ratios in oscillating flows at a zero attack angle with non-zero mean velocities were investigated numerically in a two-dimensional sense. At a high Reynolds number, the major parameters of the flow around a cylinder with a sinusoidal motion were the amplitude ratio of the approaching-flow velocity (AR) and the Keulegan-Carpenter number (KC), which varied respectively from 0.1 to 0.7 and 0.5 to 16. The resulting time-series wind loads on the cylinder for various AR and KC values were analyzed systematically to examine the flow effect of the rectangular cylinders.
To predict the unsteady turbulent flow around the rectangular cylinders, a weakly-compressible-flow method together with a subgrid-scale turbulence model was adopted. The resulting wind load histories were compared with the Morison equation to further find out the the corresponding values of Cd and Cd~ in the theoretical expressions based on a least-square estimation.
Results show that the numerical predictions are in good agreement with the available experimental results. Although Morison equation fails to correctly describe the time variation of lift in the case of a zero attack angle, it well describes the of the resulting drag histories in the oscillating approaching flow. Finally, the maximum drag is found when resonance occurs or when the period of the oscillating approaching flow equals the shedding period of the cylinders.
URI: http://hdl.handle.net/11455/15574
其他識別: U0005-1807200717385800
Appears in Collections:土木工程學系所

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