VELOCITY MEASUREMENTS IN ROUGHENED ANNULI.
C.J. Lawn, Matthew Hamlin · OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 1969
Velocity measurements in two annular test sections containing ribbed surfaces are related to the wall shear stresses. These were determined by location of the zero shear stress surface with a hot wire probe, and from the pressure gradient. Results confirm an earlier conclusion of the authors, based on a roughened pipe experiment, that the flow over a ribbed surface is influenced by viscosity. The nature of this influence is obscured by the scatter in the results, thought to be due to unintentional variations in rib profile from one surface to another. A method, based on these results, of predicting friction factors is described, and conclusions are drawn as to the effect of the geometry of the test section.