DOI: 10.1615/TSFP2
INFLUENCE OF A STRUCTURED WAVY SURFACE ON A TURBULENT FLOW
ABSTRACT
The influence of a train of sinusoidal waves on turbulent flow of water was studied. The waves had a height, α, of 0.5 mm and a wavelength, λ, of 5mm. The flow was such that a fully rough condition was realized. A consideration of the DNS study by Cherukat et al. (1998) of flow over a wavy wall with 2α/λ = 0.1 reveals that turbulence is sustained in a completely different way by a wavy wall than by a smooth wall. Experiments with LDV and PIV show some differences in the turbulence observed over smooth and wavy walls. However, the similarities are more striking. This is particularly evident in PIV measurements of the large scale flow structures associated with Reynolds shear stresses. These results support the notion that at a sufficient distance from the wall turbulent flows have universal structures, which depend only weakly on the structure of the wall.