arXiv subjects

Romain Castellani

Publications and source records attributed to Romain Castellani.

3 recordsLinked to original sources

arXiv2025

Extension of Sequence of Physical Processes framework relating the second Piola-Kirchhoff stress tensor to the Green-Lagrange strain tensor

An extension of the Sequence of Physical Processes using geometrical corrections of the Piola-Kirchhoff stress tensor and the Green-Lagrange strain tensor is addressed. More precisely, the usual Sequence of Physical Processes omits some geometrical non linearities that appear when the deformation becomes large. With this extension, geometrical corrections are added and let the opportunity to study rheological non linearities. Application on two famous classical viscoelastic models, namely the linear Maxwell model and the linear Kelvin-Voigt model, helps to understand how some complex behaviours may be rationalised to better understand the behaviours after some corrections.

cond-mat.soft↗

arXiv2022

Aggregation and disaggregation processes in clusters of particles: simple numerical and theoretical insights of the competition in 2D geometries

Aggregation and disaggregation of clusters of attractive particles under flow are studied from numerical and theoretical points of view. Two-dimensional molecular dynamics simulations of both Couette and Poiseuille flows highlight the growth of the average steady-state cluster size as a power law of the adhesion number, a dimensionless number that quantifies the ratio of attractive forces to shear stress. Such a power-law scaling results from the competition between aggregation and disaggregation processes, as already reported in the literature. Here, we rationalize this behavior through a model based on an energy function, which minimization yields the power-law exponent in terms of the cluster fractal dimension, in good agreement with the present simulations and with previous works.

cond-mat.soft↗

arXiv2022

Proposition of extension of models relating rheological quantities and microscopic structure through the use of a double fractal structure

Colloidal suspensions and the relation between their rheology and their microstructure is investigated. The literature showed great evidence of the relation between rheological quantities and particle volume fraction, ignoring the influence of the cluster. We propose to extend previous models using a new double fractal structure which allows, first, to recover the well-known models on the case of percolated system and, second, to capture the influence of the cluster size. This new model emphasises the necessity of such structure to account for recent experimental results. Then, the model is compared with data coming from the literature and shows close agreement.

cond-mat.soft↗