Numerical Analysis of Flow Past Two Bluff Bodies with Square-Section in Tandem Arrangement

Abstract

Abstract: The flow past two tandem squaresection bluff bodies with various spacing ratios was investigated numerically by using a second-order CBS finite element algorithm. The study mainly focuses on the effect of spacing ratios (ratio of center-to-center distance to width of bluff body) on the flow characteristics at a Reynolds number of 100. The mean drag coefficient and the root-mean-square drag and lift coefficients, the Strouhal number as well as the pressure coefficient are plotted as a function of the spacing ratio. The results reveal that spacing ratio has a great impact on the flow characteristics and the critical spacing ratio range is identified between 4.50 and 4.75， since the mean and root-mean-square force coefficients jump suddenly in this spacing ratio interval. When two bluff bodies with square-section are placed in tandem, the mean drag coefficient can be reduced effectively. The results also show that the root-mean-square lift coefficient of the downstream bluff body is always greater than that of upstream bluff body due to the wake interference. A significant difference of surface pressure coefficient distribution can also be observed.

Key words: two tandem square bluff bodies, critical spacing ratio, force coefficient

CLC Number:

TU 393.2

WU Qi-二, ZHOU Dai, FU Gong-Yi. Numerical Analysis of Flow Past Two Bluff Bodies with Square-Section in Tandem Arrangement[J]. Journal of Shanghai Jiaotong University, 2012, 46(01): 130-135.

References

［1］Okajima A. Strouhal numbers of rectangular cylinders［J］. Journal of Fluid Mechanics，1982, 123:379398.

［2］Norberg C. Flow around rectangular cylinders: Pressure forces and wake frequencies［J］. Journal of Wind Engineering and Industrial Aerodynamics, 1993, 49(1/3):187196.

［3］Breuer M, Bernsdorf J, Zeiser T, et al. Accurate computations of the laminar flow past a square cylinder based on two different methods: Latticeboltzmann and finitevolume［J］. International Journal of Heat and Fluid Flow, 2000, 21(2):186196.

［4］Sharma A, Eswaran V. Heat and fluid flow across a square cylinder in the twodimensional laminar flow regime［J］. Numerical Heat Transfer, 2004, 45(3):247269.

［5］Sahu A K, Chhabra R P, Eswaran V. Effects of Reynolds and Prandtl numbers on heat transfer from a square cylinder in the unsteady flow regime［J］. International Journal of Heat and Mass Transfer, 2009, 52(3/4): 839850.

［6］Zdravkovich M M. Review of flow interference between two circular cylinders in various arrangments［J］. Journal of Fluids Engineering, 1977, 99: 618633.

［7］Zdravkovich M M. The effect of interference between circular cylinders in cross flow［J］. Journal of Fluids and Structures, 1987, 1(2): 239261.

［8］Sumner D, Price S J, Paidoussis M P. Flowpattern identification for two staggered circular cylinders in crossflow［J］. Journal of Fluid Mechanics, 2000, 411(1):263303.

［9］Sharman B, Lien F S, Davidson L, et al. Numerical predictions of low Reynolds number flows over two tandem circular cylinders［J］. International Journal of Numerical Methods in Fluids, 2005, 47(5):423447.

［10］Kim M K, Kim D K, Yoon S H, et al. Measurements of the flow fields around two square cylinders in a tandem arrangement［J］. Journal of Mechanical Science and Technology, 2008, 22(2):397407.

［11］Lankadasu A, Vengadesan S. Interference effect of two equalsized square cylinders in tandem arrangement: With planar shear flow［J］. International Journal of Numerical Methods in Fluids, 2008, 57(8):10051021.

［12］Bao Y, Zhou D, Huang C. Numerical simulation of flow over three circular cylinders in equilateral arrangements at low Reynolds number by a second order characteristicbased split finite element method［J］. Computers and Fluids, 2010, 39(5):882899.

［13］HuheAode H, Tatsuno M, Taneda S. Visual studies on wake structure behind two cylinders in tandem arrangement［J］. Reports of Research Institute for applied Mechanics, 1985, 32:120.