The commencement of flow of a Bingham Plastic fluid

Abstract A Bingham Plastic is a fluid distinguished from ordinary Newtonian fluids by its property called ‘yield stress’, and in the present work an assessment has been made of the effect which ‘yield stress’ has on the pumping requirements for such fluids, both in the initiation of flow from rest and in the ultimate steady-state condition. This has been done by solving numerically the appropriate equations of motion. The main conclusion is that although the presence of ‘yield stress’ diminishes the steady-state flow-rate which is ultimately attained, in other respects it has a negligible effect on the character and duration of the flow build-up.