A two-dimensional numerical study is performed to investigate the relation between the
direction of a deflected wake and the vortex pairing mechanisms. The deflection angle can
be correlated with two effective phase velocities defined to represent the trends of symmetry
breaking and symmetry holding, respectively. The deflection angle increases with the
strength of the vortex pairs, which is associated with the heaving amplitude, frequency, and
the free stream Reynolds number. Furthermore, not only the influence of Strouhal number …