基于IVCBC涡方法高雷诺数下串联双圆柱的数值计算模型及其尾流特征研究
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摘要
针对串联双圆柱的结构特点,利用IVCBC涡方法适合高雷诺数下数值计算的特点,建立了高雷诺数下串联双圆柱绕流的数值计算模型;采用经典算例验证了IVCBC涡方法的收敛性;探索了雷诺数为2.5×104、间隙比分别为1.1,1.25,2,2.5,3,3.25和4的串联双圆柱绕流的尾流特征;清晰地展示了尾流中较小的漩涡的形成、分裂和融合,详细地阐述了串联双圆柱流体特征发生突变的原因;深刻地揭示了串联双圆在高雷诺数下的绕流机理。研究表明:尾流模式与经典的实验尾流模型吻合较好,两圆柱中间的涡对是串联双圆尾流发生突变的主要原因;间隙之间时,间隙上部小漩涡形成、间隙中间流体的振动与下游圆柱表面上涡的脱落是同步的;该流体模式能清晰地展示尾流中较小漩涡,说明与有网格方法比较,该计算模型具有较大的优越性,为进一步研究高雷诺数下串联双圆柱流体力的特征提供了重要的研究工具。
Based on the characteristic of two circular cylinders in tandem, the numerical computation model under high Reynolds number was established with the characteristics that IVCBC vortex method suits for computing under high Reynolds number. The convergence of IVCBC vortex method was validated by the classical cases. Wake characteristics of double circular cylinders were investingated under Reynolds number 2.5×104 and gap ratios 1.1, 1.25, 2, 2.5, 3, 3.25 and 4. Generation, split and merger of small vortex in wake were shown clearly. The reason of wake mutation and characteristics of flow around two circular cylinders in tandem was explained detailedly. The study shows that wake models are in good agreement with that of classical experimental model, and the vortex pair between two cylinders is the main reason of wake mutaion. At small gap ratios, formation of the small vortex on top of gap and the vibration of flow inside gap is cynchronization with shedding of vortex on the surface of downstream cylinder. It is large advantages of the simulation model compared with the grid methods because the simulation model can show the small vortex in wake. It provides an important tool to study further the characteristics of flow force of double cylinders in tandem.
Based on the characteristic of two circular cylinders in tandem, the numerical computation model under high Reynolds number was established with the characteristics that IVCBC vortex method suits for computing under high Reynolds number. The convergence of IVCBC vortex method was validated by the classical cases. Wake characteristics of double circular cylinders were investingated under Reynolds number 2.5×104 and gap ratios 1.1, 1.25, 2, 2.5, 3, 3.25 and 4. Generation, split and merger of small vortex in wake were shown clearly. The reason of wake mutation and characteristics of flow around two circular cylinders in tandem was explained detailedly. The study shows that wake models are in good agreement with that of classical experimental model, and the vortex pair between two cylinders is the main reason of wake mutaion. At small gap ratios, formation of the small vortex on top of gap and the vibration of flow inside gap is cynchronization with shedding of vortex on the surface of downstream cylinder. It is large advantages of the simulation model compared with the grid methods because the simulation model can show the small vortex in wake. It provides an important tool to study further the characteristics of flow force of double cylinders in tandem.
引文
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[13]Pang Jianhua,Zong Zhi,Zou Li.Numerical simulation of the flow around two side-by-side circular cylinders by IVCBC vortex method[J].Ocean Engineering,2016.
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[16]Igarashi T.Characteristics of the flow around two circular cylinders arranged in tandem:1st report[J].Bulletin of JSME,1981,24(188):323-331.
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[2]Li J,Chambarel A,Donneaud M.Numerical study of laminar flow past one and two circular cylinders[J].Computers&Fluids,1991,19(2):155-170.
[3]Johnson A A,Tezduyar T E,Liou J.Numerical simulation of flows past periodic arrays of cylinders[J].Computational Mechanics,1993,11(5-6):371-383.
[4]Farrant T,Tan M,Price W G.A cell boundary element method applied to laminar vortex shedding from circular cylinders[J].Computers&Fluids,2001,30(2):211-236.
[5]Hall J W,Ziada S,Weaver D S.Vortex-shedding from single and tandem cylinders in the presence of applied sound[J].Journal of Fluids and Structures,2003,18(6):741-758.
[6]Meneghini J R,Saltara F,Siqueira C L R.Numerical simulation of flow interference between two circular cylinders in tandem and side-by-side arrangements[J].Journal of Fluids and Structures,2001,15(2):327-350.
[7]Sharman B,Lien F S,Davidson L.Numerical predictions of low Reynolds number flows over two tandem circular cylinders[J].International Journal for Numerical Methods in Fluids,2005,47(5):423-447.
[8]Ding H,Shu C,Yeo K S.Numerical simulation of flows around two circular cylinders by mesh-free least square-based finite difference methods[J].International Journal for Numerical Methods in Fluids,2007,53(2):305-332.
[9]Jian D,An L R,Jian F Z.Three-dimensional flow around two tandem circular cylinders with various spacing at Re=220[J].Journal of Hydrodynamics,Ser.B,2006,18(1):48-54.
[10]Singha S,Sinhamahapatra K P.High-resolution numerical simulation of low Reynolds number incompressible flow about two cylinders in tandem[J].Journal of Fluids Engineering,2010,132(1):011101.
[11]Pang Jianhua,Zong Zhi.Improving Discrete vortex method for investigation of the fluctuating forces acting on a circular cylinder at subcritical Reynolds number[C]//Proceedings of 3rd International CFD Conference.Dalian,China,2014.
[12]Pang Jianhua,Zong Zhi,Zou Li.A novel vortex scheme with instantaneous vorticity conserved boundary conditions[J].European Journal of Mechanics/B Fluids,2016.
[13]Pang Jianhua,Zong Zhi,Zou Li.Numerical simulation of the flow around two side-by-side circular cylinders by IVCBC vortex method[J].Ocean Engineering,2016.
[14]Kideok R,Zhu B S,et al.Numerical analysis of unsteady viscous flow through a Weis-Fogh-type ship propulsion mechanism using the advanced vortex method[J].ASME Journal of Fluids Engineering,2006,128:481-487.
[15]Blevins R D.Applied fluid dynamics handbook[M].Van Nostrand Reinhold CO,1984.
[16]Igarashi T.Characteristics of the flow around two circular cylinders arranged in tandem:1st report[J].Bulletin of JSME,1981,24(188):323-331.
[17]Zdravkovich M M.The effects of interference between circular cylinders in cross flow[J].Journal of Fluids and Structures,1987,1(2):239-261.
[18]Zdravkovich M M.Flow around circular cylinders:volume 2:applications[M].Oxford:Oxford University Press,2003.
[19]Ljungkrona L,Norberg C H,Sunden B.Free-stream turbulence and tube spacing effects on surface pressure fluctuations for two tubes in an in-line arrangement[J].Journal of Fluids and Structures,1991,5(6):701-727.