Exploring rheological variability in different geophysical flows

Abstract

This study focuses on understanding how natural mass movements; such as debris flows, mudflows, and granular density currents; behave under varying environmental conditions. Rheology, the science of deformation and flow of matter, plays a central role in predicting flow dynamics. We analyse rheological properties across both Newtonian and non-Newtonian flow regimes. Within the non-Newtonian flow regimes, rheological models such as Bingham, Herschel-Bulkley, quadratic, and bilinear are studied, focusing the relationship between shear stress and shear rate across several parametric ranges. Furthermore, this paper primarily emphasizes a study of the theoretical foundations of several rheological models, including Bagnold’s grain-inertia theory, Mohr–Coulomb plasticity, and the µ(I)-rheology. Our comparative analyses highlight the critical need for adaptive, multi-phase rheological formulations in geophysical mass flow modelling. The insights gained contribute to bridging the gap between idealized rheology and field-scale flow behaviour, paving the way for next-generation models that incorporate dynamic solid-fluid interactions for more accurate hazard prediction and mitigation.