About Us
Knowledge of physical properties of fluids associated with their deformation and flow are essential in the
development of physical models that accurately mimic their behaviour. Formulation of such models not only
provide major academic challenges to students of Rheology, but finds ready applications spanning a range of
disciplines, including development of new materials, design of process equipment, biomedical engineering and
fuel technology. The accurate measurement of fluid characteristics is also a significant technological challenge,
and with its many applications in, among others, medical and industrial fields, is essential for evaluating new
rheological models and the numerical techniques of their solution.
Rheometry is concerned with experimental characterisation of non-Newtonian fluids in the construction of
rheological equations of state (constitutive equations) which are fundamental to analytical considerations
of the more practical situations, such as transportation of particulates, flow mixing and sedimentation.
Traditionally, sedimentation of single spheres have been used in the determination of viscosity of Newtonian fluids.
Application to non-Newtonian fluids is complicated by shear rate dependence of viscosity, finite relaxation
times as well as elasticity that some fluids have been found to possess.
The latter phenomenon may give rise to an unsteady sedimentation rate, invalidating the simplicity of the
falling sphere technique, while the former observation may necessitate long time intervals between consecutive
sedimentation tests.
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Rheology group has been looking at the manufacture and the flow of various articles and has been involved in:
- Characterisation of viscoelastic materials (eg. bread dough/ soft tissue/ molten plastics or polymers/
suspensions) through a series of rheologically correct tests.
- Constitutive modelling, through either a microstructural-based or continuum-based method (eg. the
realistic modelling of polymer-processing, incorporating the effects of compressibility, crystallisation,
and liquid-solid phase change).
- Setting up general purpose Finite Element Method, Boundary Element Method or Finite Volume Method programs
to study common processes including mixing and extrusion, optimisation of mixing equipment and designs of new
rheological instruments. Parallel computational methods are being introduced, giving exceptionally short solution
times.
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