Distributions of the density-weighted average of the perpendicular (top row) and parallel (bottom row) component of the surrounding gas velocity relative to the filaments’ one at varying offsets from the filament crest. The dot-dashed lines give a reference sound speed of 0.24 km s⁻¹, proper of a molecular medium at 10 K. The two simulations High_B (left column) and Low_B (right column) are shown at SFE = 3%. From the heatmaps, it is visible how the bulk of V_⊥ distributions (top) drop to negative at larger offsets, that is infalling, velocities at larger offsets, stalling around −0.5 km s⁻¹. In V_∥ distributions, a similar trend is visible in μ = 8 filaments, where the negative velocities individuate faster flows inside of the filament than outside. Such behaviour is less visible in μ = 2 filaments.