Fig. 3: Streamer formation.
From: The role of fluid friction in streamer formation and biofilm growth
Frame a illustrates the mechanism of streamer formation. Floating particles are transported by the flow until they reach an attachment point (1). They are then stretched by fluid forces (2) and (3) until they reach their final length. Frame b shows a microcolony at t1 = 54.25 h and t2 = 58.75 h. Between these two instances, a streamer with a length of approximately 50 μm develops. Frames c and d visualise the flow field around a leaning pillar in a shear-driven flow at Recyl = 1, representative of a microcolony from Fig. 2. c shows streamlines, while d depicts the vertical velocity component in the centre-plane of the cylinder. The flow direction is indicated by the red arrow, with secondary motions converging downstream, near the pillar tip, where longitudinal shear increases to roughly three times the driving shear stress.
