TY - JOUR
T1 - Spontaneous Negative Entropy Increments in Granular Flows
AU - Laudani, Rossella
AU - Ostoja-Starzewski, Martin
N1 - Funding Information:
Expert comments on LAMMPS by S. J. Plimpton (Sandia National Laboratories) and on Couette flows by R. E. Khayat (University of Western Ontario) are appreciated. R. L. acknowledges support by the University of Messina. The work of MO-S was funded, in part, by the National Institute of Biomedical Imaging and Bioengineering of the NIH under award R01EB029766.
Publisher Copyright:
© 2020 Royal Society of Chemistry. All rights reserved.
PY - 2021/3/1
Y1 - 2021/3/1
N2 - The entropy inequality, commonly taken as an axiom of continuum mechanics, is found to be spontaneously violated in macroscopic granular media undergoing collisional dynamics. The result falls within the fluctuation theorem of nonequilibrium thermodynamics, which is known to replace the Second Law for finite systems. This phenomenon amounts to the system stochastically displaying negative increments of entropy. The focus is on granular media in Couette flows, consisting of monosized circular disks (with 10 to 104 disks of diameters 0.01 m to 1 m) with frictional-Hookean contacts simulated by molecular dynamics accounting for micropolar effects. Overall, it is determined that the probability of negative entropy increments diminishes with the Eulerian velocity gradient increasing, while it tends to increase in a sigmoidal fashion with the Young modulus of disks increasing. This behavior is examined for a very wide range of known materials: from the softest polymers to the stiffest (i.e., carbyne). The disks' Poisson ratio is found to have a weak effect on the probability of occurrence of negative entropy increments.
AB - The entropy inequality, commonly taken as an axiom of continuum mechanics, is found to be spontaneously violated in macroscopic granular media undergoing collisional dynamics. The result falls within the fluctuation theorem of nonequilibrium thermodynamics, which is known to replace the Second Law for finite systems. This phenomenon amounts to the system stochastically displaying negative increments of entropy. The focus is on granular media in Couette flows, consisting of monosized circular disks (with 10 to 104 disks of diameters 0.01 m to 1 m) with frictional-Hookean contacts simulated by molecular dynamics accounting for micropolar effects. Overall, it is determined that the probability of negative entropy increments diminishes with the Eulerian velocity gradient increasing, while it tends to increase in a sigmoidal fashion with the Young modulus of disks increasing. This behavior is examined for a very wide range of known materials: from the softest polymers to the stiffest (i.e., carbyne). The disks' Poisson ratio is found to have a weak effect on the probability of occurrence of negative entropy increments.
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U2 - 10.1115/1.4049184
DO - 10.1115/1.4049184
M3 - Article
C2 - 34168386
AN - SCOPUS:85097647011
SN - 0021-8936
VL - 88
JO - Journal of Applied Mechanics, Transactions ASME
JF - Journal of Applied Mechanics, Transactions ASME
IS - 3
M1 - 031010 EN
ER -