Wall Effects in Permeameters

by Colin R. Dudgeon,


Serial Information: Journal of the Hydraulics Division, 1967, Vol. 93, Issue 5, Pg. 137-148


Document Type: Journal Paper

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Abstract: The effect of a permeameter wall on the mean flow velocity measured in a permeameter containing granular material is investigated. The difference between the measured mean flow velocity and a true one-dimensional velocity in an infinite medium is attributed to a much higher than average flow rate in a narrow zone of high porosity immediately adjacent to the wall. An equation for the ratio of measured to true velocity is derived. Data from an experimental investigation into the velocity-hydraulic gradient relationship for coarse granular media at various porosities are combined with the results of wall-zone porosity measurements to predict values of the ratio. Measured values of this ratio for 16-mm diameter glass marbles and 3 / 4-in. river gravel in a 22.5-in diameter permeameter are compared with calculated values.

Subject Headings: Flow measurement | Walls | Fluid velocity | Granular materials | One-dimensional flow | Porosity | Flow rates | Glass

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