Particle-scale structure of granular suspensions
Abstract
Granular suspensions are intrinsically nonequilibrium systems in which dissipative grain-grain collisions coexist with solvent-induced forcing. We study the particle-scale structure of a granular suspension modeled by smooth inelastic hard spheres immersed in a thermal bath and compare Langevin-dynamics simulation results for the radial distribution function g(r) and the static structure factor S(q) with predictions of an equilibrium-inspired rational function approximation (RFA). The equilibrium hard-sphere RFA is supplied with nonequilibrium input for the contact value and a reduced isothermal-compressibility-like quantity, yielding analytical expressions for g(r) in Laplace space and for S(q). We find that the RFA gives a very good description of the short- and intermediate-range structure of the suspension over a broad range of densities, drag coefficients, and inelasticities. It reproduces g(r) substantially better than the Percus-Yevick approximation in inelastic states, especially near contact, and gives a good account of S(q) except at the smallest wave numbers. There, simulations show a drag-dependent enhancement over the RFA prediction, indicating additional long-wavelength nonequilibrium correlations beyond the present equilibrium-like description. These results show that an equilibrium-based hard-sphere approach provides an accurate description of the particle-scale structure of the present Langevin model with inelastic hard spheres (except in the smallest-q region), and suggest that similar equilibrium-inspired approaches may also be useful for related nonequilibrium hard-sphere suspension models, including multicomponent systems.
Versions
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BibTeX
@misc{yuste2026particlescale,
title = {{Particle-scale structure of granular suspensions}},
author = {Santos Bravo Yuste and Antonio M. Puertas},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2607.18090},
eprint = {2607.18090},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.18090},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Particle-scale structure of granular suspensions
AU - Santos Bravo Yuste
AU - Antonio M. Puertas
PY - 2026
DA - 2026/11/02
PB - arXiv
DO - 10.48550/arxiv.2607.18090
UR - https://arxiv.org/abs/2607.18090
AB - Granular suspensions are intrinsically nonequilibrium systems in which dissipative grain-grain collisions coexist with solvent-induced forcing. We study the particle-scale structure of a granular suspension modeled by smooth inelastic hard spheres immersed in a thermal bath and compare Langevin-dynamics simulation results for the radial distribution function g(r) and the static structure factor S(q) with predictions of an equilibrium-inspired rational function approximation (RFA). The equilibrium hard-sphere RFA is supplied with nonequilibrium input for the contact value and a reduced isothermal-compressibility-like quantity, yielding analytical expressions for g(r) in Laplace space and for S(q). We find that the RFA gives a very good description of the short- and intermediate-range structure of the suspension over a broad range of densities, drag coefficients, and inelasticities. It reproduces g(r) substantially better than the Percus-Yevick approximation in inelastic states, especially near contact, and gives a good account of S(q) except at the smallest wave numbers. There, simulations show a drag-dependent enhancement over the RFA prediction, indicating additional long-wavelength nonequilibrium correlations beyond the present equilibrium-like description. These results show that an equilibrium-based hard-sphere approach provides an accurate description of the particle-scale structure of the present Langevin model with inelastic hard spheres (except in the smallest-q region), and suggest that similar equilibrium-inspired approaches may also be useful for related nonequilibrium hard-sphere suspension models, including multicomponent systems.
ER -