Surface density distributions of gas (top row) and grown dust (bottom row) with the superimposed velocity fields that illustrate distinctive flows in different types of tail-like structures: post-collisional tails (left column), pre-collisional tails (middle column), and spiral tails (right column). The cyan and white arrows indicate the velocity fields of gas and grown dust, respectively. The arrow length is in the log scale. The arrows of maximum length correspond to 4.3 km s⁻¹. The gas and dust color scale bars are in log g cm⁻².