RESEARCH
My research focusses on modelling and understanding the motion of contact lines, contact lines being the location at which two immiscible fluids and a solid substrate meet. They arise in a wide range of both natural and technological processes, from insects walking on water and the wetting properties of plant leaves to coating, inkjet printing, and oil recovery. Understanding of the moving contact line remains a persistent problem and a long-standing and fundamental challenge in the field of fluid dynamics.
The crux of the moving contact line problem is that, when treated classically as two immiscible fluids with a sharp interface moving along a solid surface satisfying the no-slip condition, there is no solution due to a multivalued velocity at the contact line. The problem is of such interest as there are many physical effects which occur on the microscale and are not included in the classical description, which may influence and help to resolve this problem. In my recent research, alongside others from the group, we have considered some of the more complex, yet physical and universal effects, and attempted to reconcile these models with their classical macroscopic counterparts.
Specifically, we have investigated a complex continuum model, namely the interface formation model, in the prototype system of droplet spreading in the lubrication approximation using matched asymptotic methods and numerical pseudo-spectral methods, and compared it to more common models based on slip at the solid surface. We are also investigating diffuse-interface approaches for liquid-gas and liquid-liquid systems, based on the physically motivated model that the interface, even between ostensibly immiscible fluids, is not sharp but thin.