Revolving flow of a fluid-particle suspension with suction

The three-dimensional revolving flow of a particle-fluid suspension above a plane surface is considered. The flow represents an extension of the classical Bödewadt flow to a two-fluid problem. The governing equations for the two phases are coupled through an interaction force with the particle relaxation time τ as a free parameter. By means of a similarity transformation, the coupled set of non-linear ODEs becomes a two-point boundary value problem. The numerical results show that the radial inward particle velocity increases whereas the circumferential velocity decreases by shortening τ , thereby strengthening the spiralling particle motion. These predictions are consistent with the so-called tea-cup effect, i.e. accumulation of tea leaves at the centre of the cup. On the contrary, the revolving fluid motion is reduced as a result of the particle-fluid interactions.