DOI: 10.5281/zenodo.15798936
title: Data set dense granular flow of elongated and flattened particles

description: This is the data set used supporting the publication of "Shear flow of frictional spheroids: Comparison between elongated and flattened particles" by Jacopo Bilotto, Martin Trulsson, and Jean-Fran\c{c}ois Molinari, in Physical Review E.DOI: https://doi.org/10.1103/tj41-6qqk. 

It contains several rheological and microscopic properties of granular flows of spheroids at small-medium inertial numbers.The data is available for different aspect ratios and coefficient of frictions, with the naming simple_shear_ap{aspect_ratio}_cof_{friction}_I_{inertial_number}.pkl

More details can be found in the description.
description: This dataset contains the results of numerical simulations stored in individual Python pickle (.pkl) files. Each file corresponds to a single simulation run and contains a Python dictionary with various physical and computational quantities measured or derived during the simulation. These quantities include time-dependent observables, diagnostic metrics, and simulation parameters, structured in a consistent format across files to facilitate post-processing and analysis.



percent_aligned: the fraction of particles whose axis of symmetry makes an angle of less than pi/4 with the xz plane (prolate), xy plane (oblate)

S2: nematic order parameter

Omega_x, Omega_y, Omega_z: The components of the mean angular velocity vector (Ω) along the x, y, and z axes, respectively

tke: translational component of the fluctuating kinetic energy

rke: rotational component of the fluctuating kinetic energy

omega_fluctuations: A 3-component array representing the root-mean-square (RMS) average fluctuation of the angular velocity components

vx_fluctuations, vy_fluctuations, vz_fluctuations: RMS average fluctuation of the velocity components in the x, y, and z directions, respectively

kinetic_stress: A 3×3 tensor representing the kinetic stress in the system

measured_shear_rate: The observed or computed shear rate in the system

c_r_values: The spatial separation distances (r) corresponding to the autocorrelation functions like c_delta_vy and c_delta_omega_z

c_y_values: The spatial separation distances (y) corresponding to the correlation function c_density_y

c_density_y: The spatial correlation of density along y (used to check smectic ordering)

c_delta_vy: The spatial autocorrelation function of the velocity fluctuations in the y-direction

c_delta_omega_z: The spatial autocorrelation function of the fluctuations in the z-component of angular velocity

box_x_length, box_y_length, box_z_length: The physical dimensions of the simulation domain along the x, y, and z axes, respectively. Along y the dimension is averaged

Z: The average coordination number — the mean number of contacts per particle in the system

percent_sliding: The fraction of inter-particle contacts that are sliding (as opposed to sticking)

stress_contacts: The contact stress tensor, derived from inter-particle contact forces and positions

shear_stress_normal: The component of the contact stress tensor attributed to normal forces (perpendicular to contact surfaces)

shear_stress_tangential: The tangential (or frictional) contribution to the shear stress tensor, resulting from forces parallel to contact surfaces

fabric: The fabric tensor computed with the contact normals

muI_dissipation: Energy dissipation estimated based on the μ(I) rheology framework

thetax_mean, thetaz_mean: Circular mean angles (in radians) around the x axis in the xy-plane and the z axes in the xz, respectively

shear_rate: The externally imposed or internally measured shear rate of the system. This scalar value quantifies the rate of deformation due to shear, playing a key role in flow characterization and rheology

area_adjustment_ellipsoid: A 10 element array representing the surface area of the spehroids polar slices, from 0 to pi/2

total_area: The total surface area of the average radius particles

total_normal_dissipation: The total power dissipated through normal contact forces (perpendicular to contact surfaces)

total_tangential_dissipation: The total power dissipated through tangential (frictional) contact forces

pdf_thetax, pdf_thetaz: probability distribution of the angles whose means are thetax_mean and thetaz_mean respectively

auto_corr_vel: The temporal autocorrelation function of particle velocity fluctuations in the y direction

auto_corr_omega: The temporal autocorrelation function of angular velocity fluctuations in the z direction

strain: A uniformly spaced array representing the accumulated shear strain in the system, used to compute the temporal autocorrelations

inertialNumber: The dimensionless inertial number (I) measured troughtout the simulation

phi: The solid volume fraction in the system

press: The average isotropic pressure within the system, from the trace of the stress tensor

p_yy: The component of stress tensor acting along the y-axis (normal stress in y direction)

p_xy: The shear stress component acting in the plane defined by x and y directions

Nx_diff, Nz_diff: First and second normal stress differences resepctively

Dyy, Dzz: Diffusion coefficients along the y and z directions, respectively

contacts_hist_global_normal, contacts_hist_global_tangential: Histogram contact forces measured in the normal and tangential direction, respectively

power_dissipation_normal, power_dissipation_tangential: array of normal and tangential power dissipation accumulated on a single particle at constant polar angle spacing on the surface

contacts_hist_cont_point_local / bin_counts_power: density of contacts per spheorid surface slice


Note: All the following quantities are measured at discrete, equally spaced slices along the y-axis.



Ncount_avg & Ncount_std_dev: Average number of particles counted and its std

vx_avg & vx_std_dev: Mean velocity component in the x-direction and its std

vy_avg & vy_std_dev: Mean velocity component in the y-direction and its std

vz_avg & vz_std_dev: Mean velocity component in the z-direction and its std

c_omegaz_avg & c_omegaz_std_dev: Average angular velocity about the z-axis and its std

density_mass_avg & density_mass_std_dev: Average local mass density and its std

v_pxx_loc_avg & v_pxx_loc_std_dev: Average normal stress in the x-direction and its std

v_pyy_loc_avg & v_pyy_loc_std_dev: Average normal stress in the y-direction and its std

v_pzz_loc_avg & v_pzz_loc_std_dev: Average normal stress in the z-direction and its std

v_pxy_loc_avg & v_pxy_loc_std_dev: Average shear stress in the xy-plane and its std