Raman Research Institute

बेंगलूरू /Bengaluru

SCM - WIP Seminar

Title: 'Saffman-Taylor instability in clay suspensions'

Speaker: Vaibhav Raj Singh Parmar

Date & Time:  Friday, 23 May 2025 at 2:30 pm

Venue: SCM lecture hall

Abstract:  Patterns are found everywhere in nature across different length scales, ranging from microscopic snowflakes, river networks and lightning. Pattern formation is driven by instabilities in systems out of equilibrium. An instability arises from the self-amplification of small perturbations. When an aging, viscoelastic fluid is displaced by a Newtonian fluid, a rich array of interfacial patterns is generated due to a predominantly viscous instability. In this talk, I shall discuss how we controlled the mechanical properties of aging aqueous colloidal clay suspensions by incorporating additives. We carefully studied the interfacial patterns that resulted when clay suspensions with and without additives were displaced by a miscible Newtonian fluid in a radial Hele-Shaw cell. We show here that interfacial pattern dynamics and morphologies can be fine-tuned via the appropriate selection of aging-enhancing and aging-delaying additives. Furthermore, by tuning the nature and content of the aging-delaying additives, we demonstrate the existence of two novel propagation mechanisms, pattern growth via skewering and zig-zag finger propagation. These patterns have hitherto never been observed in experiments with colloidal systems. Our work demonstrates that the incorporation of additives during the confined displacement of clay suspensions by miscible Newtonian fluids is an effective strategy to manipulate the onset and growth of interfacial instabilities.

सभी का स्वागत है /All Are Welcome