Thin film Flow on Functional Surfaces: Stability and Morphology

The research to be undertaken encompasses a theoretical investigation of thin film (Newtonian and non-Newtonian) flows on functional surfaces embodying the appropriate physics. Such flows are ubiquitous within the processing and manufacturing industries. The focus will be: (a) the stability of continuous films on regular, topographically patterned, surfaces; (b) the morphology associated with the partial coverage and de-wetting characteristics of thin films spreading over a partially wetting surface when the latter is chemically homogeneous or chemically patterned leading to sudden changes in the surface energy at prescribed sites. The principal vehicle for deriving appropriate predictive models for the behaviour of the evolving three-dimensional flow for both problems will be the long-wave approximation; the resulting equation set will be solved computationally using state-of-the-art numerical approximations and convergence acceleration algorithms, utilising parallel programming and computing platforms as necessary. An additional simplifying assumption is that evaporation effects will be ignored. In all cases the main diagnostic will be the free-surface shape and deformation relating this, where possible, to the underlying flow structure within the fluid film. The latter will be relatively straight forward for the simplified two-dimensional case of problem (a) and for isolated topographical features in three-dimensions, but will be considerably more challenging for problem (b) - other than in isolated regions of the flow where the film breaks up to form a droplet which can be explored individually.