Rough-wall boundary layers in adverse pressure gradients

Abstract

Smooth- and rough-wall boundary layers and fully developed pipe and duct flow investigations are reviewed. It is shown that the effect of roughness on the flow away from the wall can be accounted for by using an equivalent viscosity νe. This viscosity is thought to depend only on the variables at the wall, such as shear stress τ0, fluid density ρ, viscosity μ and the roughness size and geometry and that the relationship between these variables is the same for both boundary layers and duct flow. However, experiments to date have been confined to the ‘rough régime’ and to boundary layers with a zero pressure gradient.Experiments were performed and the results show that the above finding can be extended to boundary layers with adverse pressure gradients in the rough régime.A general method for measuring the local boundary-layer characteristics, with roughness and pressure gradients present, is developed.

Re-examination of the scaling roughness function for κ-type rough walls using a servo-controlled wall drag balance

“…in disagreement with the classical representation of Perry and Joubert (1963) or Liu et al (1966). As we underlined and discussed in our paper, an unfortunate error was made regarding the geometry of the floating head, in that the length chosen did not correspond to an integer number of roughness wavelengths (i.e.…”

The frictional resistance induced by bacterial based biofouling in drainage pipelines

“…Consequently, a wall origin correction, ε, was applied. An adaptation of the method proposed by Perry and Joubert (1963) was integrated into the PL method in order to solve for ε and 5 * simultaneously using an iterative approach.…”

Experimental technique and assessment for measuring the convective heat transfer coefficient from natural ice accretions

“…Due to the coupled nature of the momentum and heat transfer problem, later investigations usually considered both the fluid mechanics and the heat Perry and Joubert [1963] studied the effect of roughness using plates with a traverse length of 17 ft in a wind tunnel having an adverse pressure gradient The roughness consisted of 800 strips of timber which were 5 ft and 3 in long. The spacing to height ratio then was 4.…”