Secondary flow vortices and their effect on fluid-solid transport

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This project aims to improve fundamental understanding regarding the interaction of various applied flow fields, and particularly so-called "secondary-flow" vortices, with solid particles. A series of simplified geometries will be chosen to study a wide range of flow conditions for both Newtonian and complex fluids, in the presence/absence of vortices, and its interaction on the solids bed in a controlled and systematic manner. This knowledge will then be used to update or generate new models for the solid's transport, settling, bed formation and resuspension criteria.Analytical solutions concerned with Newtonian fluid flow in various geometries are readily available from many sources. However, the same cannot be said of viscoelastic fluids. One aspect of this project will look at developing analytical solutions for such fluids in a series of geometries that develop secondary flows. We will then further expand these solutions, where possible, by considering various flow conditions as well as the interaction of these flow fields with solid particles. Given the complex rheologies of the fluids concerned, coupled with the addition of solid transport, we will also be considering several numerical and experimental techniques, where appropriate. We anticipate that this will lead to the development of new models of industrial significance. Another aspect of the project will focus on the T-channel geometry for complex fluid flows. Whilst Newtonian fluids are an ideal model for analytical solutions - the reality is that most fluids are non-Newtonian. For such fluids, there is always a possibility of flow instabilities. The very presence of these instabilities adds a further complication to the problem. Given the complexity of the problem, we will employ the use of the numerical and experimental techniques available to us.Subsequently, we will then consider the same T-channel geometry with a solids bed. Given that the geometry with a complex fluid flow is already a relatively intricate problem, we plan to use a combination of numerical simulations and experiments for this particular problem; and we envisage that this will allow us to develop appropriate new models for industrial applications. In the interest of completeness, we will also consider a Newtonian fluid for a T-channel with a solids bed.