数值求解了二维浅水方程和RNG k-ε流模型，模拟了不同稳定性系数S和圆柱中心间距G下的单圆柱、两圆柱和三圆柱的尾流流动模式，研究了底部摩擦力对尾流结构的影响。结果表明:随着S增大，尾流在底部摩擦力的作用下趋于稳定，大尺度涡结构逐渐消失。单圆柱尾流区依次出现了涡街（VS）尾流、不稳定漩涡（UB）尾流和稳定漩涡（SB）尾流。多圆柱尾流除了受S数影响外，还与G密切相关。随着G的增大，两圆柱背后依次出现了单钝体绕流、偏转尾流和对称尾流，三圆柱背后则依次出现了单钝体绕流、偏转尾流、对称尾流和非对称尾流。此外，数值结果还表明多圆柱尾流结构不同于单圆柱，多圆柱并排使得尾流更加不稳定。

The paper numerically investigates flow structures of single, two and multiple cylinders arranged in a shallow water flow. The shallow wakes are simulated with different shallow wake parameters and cylinder center-to-center spacings to investigate the effect of bottom friction and geometry on wake structures. The results show that with the increase of parameter, wakes tend to steady due to the increasing bottom friction, and large-scale vortex structures disappear gradually. Wakes behind multiply cylinders are influenced not only by parameter but also by spacing with the increase of spacing. Vortex street wake, unsteady vortex wake and steady vortex wake appear behind the single cylinder, sequentially. The single blunt body wake, biased and symmetry wakes occur behind two cylinders, and the single blunt body circumfence, biased wake, symmetry and asymmetry wakes appear behind three cylinders, sequentially. Besides, simulated results indicate that wake structures of multiply cylinders are different from that of single cylinder. The arrangement of multiply cylinders makes wakes more unsteady.