NUMERICAL-ANALYSIS OF 3-DIMENSIONAL BINGHAM PLASTIC-FLOW

The present paper considers the problem of predicting motionless regions and true plug (constant velocity areas where the stress is below the yield stress) regimes for fully three-dimensional Bingham plastic flows. Numerical solutions are obtained using a finite-element biviscosity formulation. Comparisons are drawn to alternative numerical approximations and a review of common finite elements is made with a view to finding accurate, stable and economical schemes. A number of elements are compared and we conclude that some of the Fortin elements are most useful on the grounds of computational overhead and solution accuracy. These are used to investigate axial flows of a Bingham body in an annulus. Finally, we show that the numerical solutions of the axial flow of a Bingham plastic in a narrow eccentric annulus show good agreement with observations and theoretical predictions.