Showing papers by "Jørgen Fredsøe published in 1987"

Turbulence in Oscillatory Boundary Layers

Abstract: This paper reports the results of an experimental investigation on the turbulent oscillatory boundary layer flows which occur over both the smooth and rough walls, the rough wall case having a roughness parameter, the amplitude-to-roughness-height ratio of 1800. The boundary layer properties are found to be strongly dependent on the phase as well as on the wall category.

Lift Forces on Pipelines in Steady Flow

Abstract: This paper considers the lift forces acting on a pipe with or without a small gap between the pipe and the seabed. From simple physical considerations, it is explained why the potential theory that predicts a downward lift force fails. A modified description of the potential flow in front of the pipe is developed, from which the lift force is evaluated if the undisturbed flow has no velocity gradients (shear‐free flow). The paper also discusses the effect of shear on the lift coefficient. The theoretical findings are supported by experiments.