Mixing properties of a viscoelastic fluid Part II: in a closed cylindrical cavity flow

Abstract

The laminar flow of Newtonian and non-Newtonian fluids with constant and variable shear-rate parameters are studied theoretically. Numerical solutions for the concentration, particle path are obtained using finite differences and A.D.i. method in 3D cylindrical cavity. Mixing properties are investigated by tracking the motion of a number of selected fluid particles and by simulating the dispersive mixing of a 'coloured' fluid injected into the cavity while at rest in both cylinder and concentric cylinder driven flow. The stability of consentration intensity is investigated for a wide range of Newtonian and non-Newtonian fluids. The effects of inertia and elasticity are of particular interest. The instabilities are characterised by control parameters: the Reynolds, Weisenberg and Schmidt numbers.