A THEORY OF FLOW OF PARTICULATE SOLIDS IN CONVERGING AND DIVERGING CHANNELS BASED ON A CONICAL YIELD FUNCTION

It has been evident for some time that the theory of flow developed by the author twenty-five years ago is flawed. While the design method based on that theory is adequate in the design of mass-flow hoppers, it predicts incorrect channel flow angles in funnel flow and, hence, is useless in predicting the location of the level at which a funnel-flow channel meets the cylinder wall of a silo. That location is needed in the structural design of silos. The theory introduced in this paper appears to correct that flaw. The correction is obtained by replacing the modified Tresca yield pyramids of the original theory with conical yield surfaces and relating the strain rates to the stressses by the Levi flow rule. In this paper, conditions of flow are analyzed.