Collapse of a cylinder of Bingham fluid

Abstract

The ``Slump Test" is a simple method of measuring the yield stress of certain materials such as concrete and concentrated suspensions. In this procedure a cylindrical test sample is allowed to deform under its own weight, and the yield stress is obtained from the change in height (slump height) of the sample using an empirical calibration curve. In this paper the slump height/yield stress relationship of the material, considered as a Bingham fluid, is investigated numerically using a finite volume procedure applied to a homogeneous two-fluid (liquid-air) model representing flow of an equivalent single phase with variable properties. Advection is approximated using a van Leer flux limiter to reduce interface smearing without the occurrence of spurious oscillations. Predictions are in reasonable agreement with published experimental data for high yield stress materials, but are less satisfactory when the yield stress is low.