Streamwise vorticity in a turbulent pipe flow at Reτ=1000
Frontal view on the gravity-driven film flow of the silicon oil over a flat incline (a) and over the bottom corrugations (b) at otherwise identical parameters. Flow is from top to bottom. Dark horizontal lines in (a) are travelling surface waves; short, bright vertical lines in the upper part of (b) are due to steady three-dimensional surface pattern (Al-Shamaa et al., 2023)
