Table and Figure Captions
Table 1 . Physical properties of droplet and gas.
FIG. 1 . Schematic of two equally sized droplets simultaneously impacting a flat superhydrophobic surface.
FIG. 2 . Complete-coalescence-rebound (CCR) regime. (a) Selected image sequence of impact and rebound behaviors of two droplets on a flat superhydrophobic surface with L =1.17 and We =35. The velocity fields are extracted along the mid y (b) and the midx (c) plane passing through the box. The normalized time is defined asτ =t /(ρR 03/)1/2.
FIG. 3 . Partial-coalescence-rebound (PCR) regime. (a) Selected image sequence of impact and rebound behaviors of two droplets on a flat superhydrophobic surface with L =1.67 and We =35. The velocity fields are extracted along the mid y (b) and the midx (c) plane passing through the box. The normalized time is defined asτ =t /(ρR 03/)1/2.
FIG. 4 . No-coalescence-rebound regime (NCR). (a) Selected image sequence of impact and rebound behaviors of two droplets on a flat superhydrophobic surface with L =2.00 and We =35. The velocity fields are extracted along the mid y (b) and the midx (c) plane passing through the box. The normalized time is defined asτ =t /(ρR 03/)1/2.
FIG. 5 . The normalized contact time as a function of the droplet distance at We =35.
FIG. 6 . The normalized contact time as a function of the droplet distance at various Weber numbers.
Table 1 . Physical properties of droplet and gas.