Full-stack, multiscale modelling of the rheology and fluid mechanics of complex fluids.
When a dissolved polymer is carried into a strong flow, its chains stretch, relax and reorient. It is this conformational state, rather than the composition of the fluid, that sets what the fluid does next: how a filament breaks, how much friction a turbulent pipe carries, how long a protein stays unfolded in a pump.
The CReSI Lab builds models across the whole stack, from the molecular and particle scale up to the continuum flow. Our aim is a full-stack description that connects micromechanics to macroscopic rheology and to process-scale flows, so that design can rest on predictive computation rather than empiricism. We approach constitutive modelling and non-equilibrium thermodynamics through an information-theoretic lens.
Most projects sit mainly at one of these levels while touching the others.
Brownian dynamics and Stokesian dynamics of polymer chains and suspended particles, with hydrodynamic interactions treated directly, and the coarse-graining that makes such simulations affordable at scale.
Turning what the chains do into equations a continuum solver can use, tested against rheometric data in shear, extensional and mixed flows. Includes thixotropic, elastic and yielding response where the microstructure evolves with the flow.
Whole-flow prediction and the measurement geometries that test it: liquid bridges, capillary thinning, atomisation, and the rheometers built around them.
Capillary thinning, breakup and the drop-size distributions that follow, in sprays, coatings, printing and fibre spinning, where better prediction means less wasted material and less spray drift.
How chain stretching in a turbulent flow alters momentum transport, and what that implies for the pumping energy of pipelines, district heating and cooling loops, and other large fluid networks.
The conformation-dependent behaviour of blood-borne macromolecules such as von Willebrand factor in the strong, unsteady flows inside circulatory-support devices, where unfolding governs how the molecule is processed and lost.
The group's earlier work centred on active matter and on swimming at low Reynolds number: the patterns and stresses that emerge when self-propelled rods or signalling cells drive a suspension or a tissue, and the elastohydrodynamics of flagellar propulsion, including how a sperm flagellum converts internal power into swimming and what the surrounding fluid takes back. Alongside these ran a line of collaborations on colloidal assembly, bacterial biofilms and the statistical mechanics of small systems. That work continues to inform how we think about local driving, hydrodynamic coupling and emergent transport.
A workshop bringing together leaders in the field to bridge mesoscale simulation and macroscopic modelling of complex fluids. Monash University Prato Centre, Italy · 18–20 June 2025.
Visit the S4F 2025 site →Enquiries, including from prospective students and collaborators, are welcome.
Email: prabhakar.ranganathan@monash.edu
Department: Mechanical & Aerospace Engineering, Monash University
We are looking for PhD students who want to work on the physics of polymer solutions in strong flows, approached through statistical mechanics and scientific computing. Projects are available at all three levels of description, across the three application areas above.
The current project areas, together with what a candidature involves and how to apply, are set out on the two Monash profiles: