Dense suspensions of non-Brownian particles are ubiquitous in numerous industrial and engineering applications, including chocolate paste, concrete mix, ceramic paste, polishing materials, geological fluids and many more. The flow properties of these systems are affected by a wide range of parameter space including particle volume fraction, interaction between the particles, friction, solvent type, external stress and perturbation. In our group we study systems of dense suspensions using simulation and experimental rheology to understand the effects of these parameters on the flow behavior. 

Rheology of Ring Polymer Solutions: Ring polymers have a special topology which are devoid of any terminal ends. Studying the dynamics of such polymer chains become important because of their application in cloning of bacterial DNA in biotechnology, rheology modifiers in food processing industry, paint manufacturing and also useful from the perspective of modelling diffusion of active matter (such as bacteria) through porous medium, which has applications in treatment of diseases. In this work we focus on studying the rheology of ring polymer solutions in the single chain limit and in the limit of finite concentration by using Brownian dynamics simulations. The work involves mesoscale modelling of ring polymers by using bead-spring chain model and we carry out extensive numerical simulations using Brownian dynamics algorithm under various flow conditions (such as shear and extensional flows) to study the macroscopic rheology and correlate them with the microscopic configurational changes. [Attached movie showing unravelling of polymeric rings in shear flow. Courtesy: Rajat Rathi (B.Tech. Chemical Engg., 2025)]