Abstract

Understanding heat transfer and stability in processes ranging from geological flows to industrial and energy-storage applications requires accurate modeling of soft materials. Yet, as experiments and simulations become more precise, new discrepancies emerge between what we observe and what we predict, especially for complex, non-Newtonian materials. Yield-stress fluids, which behave like solids until a critical stress is reached, are commonly modeled as viscoplastic materials. While these models capture many flow features, they can miss important aspects of real flows driven by buoyancy.

In this talk, I will present recent experimental, theoretical, and numerical studies of natural convection in yield-stress fluids, revealing when and why standard models succeed or break down. The findings shed light on the physical mechanisms that control the onset and evolution of motion and point toward what the next generation of rheological models must capture.