Abstract: Flows past a pair of rotating circular cylinders in tandem arrangement at Re=100 are studied numerically.Multi-block lattice Boltzmann method(LBM) is used.Basic features of vortex shedding and forces acting on rotating circular cylinders are studied with comprehensive analysis of impact of cylindrical center spacing ratio S/D and rotational speed α.There exists a critical rotating speed at S/D=1.2,exceeding which the former cylinder produces a negative Magnus lift;As S/D=2,flow field emerges a second unstable mode similar to a single rotating cylinder;At relative large spacings(S/D=4、6),vortex sheds between cylinders.Wake flows of the later cylinder present a variety of forms of 2S、2S^*、2P、P+S and so on.

Key words: tandem circular cylinders, rotating, lattice Boltzmann method, multi-block