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

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。

Numerical computation model and wake characteristics of two circular cylinders in tandem based on IVCBC vortex method under high Reynolds number

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 num-ber 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 cylin-ders 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 mu-taion. 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 cylin-ders in tandem.