arXiv subjects

Satyabrata Patro

Publications and source records attributed to Satyabrata Patro.

3 recordsLinked to original sources

arXiv2026

Intercoupling of Segregation and Rheology in Spatially Developing Granular Chute Flows

We investigate the flow and segregation of binary granular mixtures with density differences down a long chute using a continuum framework that couples a particle-force-based segregation model with an inertial-number-based local rheology. The steady-state momentum and convection-diffusion-segregation equations are solved simultaneously, explicitly accounting for the two-way coupling between segregation and flow. Predicted concentration and velocity fields at different streamwise locations are validated against representative DEM simulations. The validated model is then used to examine the influence of density ratio, mixture composition, and chute inclination on segregation over a wide range of conditions. The chute length required to achieve fully developed segregation is quantified and compared with the development length for monodisperse granular flow. At low density ratios and/or low inclinations, segregation develops over much longer distances than the velocity field. In contrast, at higher inclinations and larger density contrasts, the two length scales become comparable, demonstrating that neglecting flow development can significantly underestimate segregation evolution.

cond-mat.soft↗

arXiv2024

Rheology of three dimensional granular chute flows at large inertial numbers

The inertial number-based rheology, popularly known as the JFP model, is well known for describing the rheology of granular materials in the dense flow regime. While most of the recent studies focus on the steady-state rheology of granular materials, the time-dependent rheology of such materials has received less attention. Owing to this fact, we perform three-dimensional DEM simulations of frictional inelastic spheres flowing down an inclined bumpy surface varying over a wide range of inclination angles and restitution coefficients. We show that steady, fully developed flows are possible at inclinations much higher than those predicted from the JFP model rheology. We show that, in addition to a modified effective friction law, the rheological description also needs to account for the stress anisotropy by means of a first and second normal stress difference law.

cond-mat.soft↗

arXiv2023

Unsteady granular chute flows at high inertial numbers

We study the time-dependent flow behavior of gravity-driven free surface granular flows using the discrete element method and continuum modeling. Discrete element method (DEM) simulations of slightly polydisperse disks flowing over a periodic chute with a bumpy base are performed. A simple numerical solution based on a continuum approach with the inertial number based $μ-I$ rheology has been proposed to predict the flow dynamics. The results of the continuum model are compared with the DEM simulation results for a wide range of chute inclinations. Solutions for the constitutive model described by the popular JFP model as well as the recently proposed modified rheological model using a non-monotonic variation of $μ-I$ are obtained. Our results demonstrate that the popular JFP model reliably predicts the flow at low to moderate inclination angles (i.e. for $I \lesssim 0.5$). However, it fails to predict the flow properties at high inclinations. The modified rheological model, on the other hand, is very well able to predict the time-averaged flow properties for all the inclination angles considered in this study. Accounting for the presence of the slip velocity, layer dilation, and stress anisotropy are found to be crucial for accurate predictions of transient flows at high inertial numbers (i.e. for $I > 1$).

physics.flu-dyn↗