低雷诺数条件下并列三圆柱绕流的尾流模式和水动力系数研究

该文应用浸入边界法对雷诺数Re(28)100和间距比T/D(28)1.1-5.0条件下的等间距并列三圆柱绕流进行了数值模拟。研究发现,尾流模式与无量纲圆柱间距比T/D密切相关,在所研究的间距比范围内共出现六种尾流模式,分别为:单体尾流模式(T/D(28)1.1-1.2)、偏斜尾流模式(T/D(28)1.3)、第一类Flip-Flopping(FF1)尾流模式(T/D(28)1.4-1.5)、第二类Flip-Flopping(FF2)尾流模式(T/D(28)1.7-2.3)、同步尾流模式(T/D(28)2.5-3.2)和调制尾流模式(T/D(28)3.3-5.0)。通过分析近尾流的涡量图、升阻力系数时程曲线和不同圆柱所受升力的相位差,详细研究了各个尾流模式的特点和联系。

Investigation on near-wake patterns and hydrodynamic coefficients of flow around three side-by-side cylinders with a low Reynolds number

Flow around three side-by-side circular cylinders with the Reynolds number of 100 was numerically investigated using the immersed boundary method.The normalized center-to-center spacing ratio T/D was from 1.1 to 5.0.It was found that the near-wake patterns highly depended on the normalized spacing ratio.With the increasing T/D,six near-wake patterns were observed,i.e.,the single-bluff-body pattern (T/D=1.1-1.2),biased gap-flow pattern (T/D=1.3),the first flip-flopping (FF1) pattern (T/D=1.4-1.5),the second flip-flopping (FF2) pattern (T/D=1.7-2.3),the synchronized pattern (T / D =2.5-3.2) and the modulated pattern (T/D =3.3-5.0).The vorticity contours in the near-wake region,the time histories of drag and lift coefficients and the phase differences between lift forces acting on different cylinders were presented.Finally,the characteristics and relations between these near-wake patterns were discussed.