TY - JOUR
T1 - Sound characteristics of disordered granular disks
T2 - Effects of contact damping
AU - Saitoh, Kuniyasu
AU - Taghizadeh Bajgirani, Kianoosh
AU - Luding, Stefan
N1 - Funding Information:
This work was supported by JSPS KAKENHI Grant Numbers 20H01868, 21H01006, and 22K03459. This work was also financially supported by 2021 Inamori Research Grants and the Information Center of Particle Technology. SL and KT acknowledge funding from the German Science Foundation (DFG) through the project STE-969/16-1 within the SPP 1897 “Calm, Smooth and Smart”.
Publisher Copyright:
Copyright © 2023 Saitoh, Taghizadeh and Luding.
PY - 2023/5/22
Y1 - 2023/5/22
N2 - We investigate numerically the sound properties of disordered dense granular packings in two dimensions. Employing linear equations of motion and excluding contact changes from our simulations, we demonstrate time evolution of sinusoidal standing waves of granular disks. We varied the strength of normal and tangential viscous forces between the disks in contact to explore the dependence of sound characteristics such as dispersion relations, attenuation coefficients, and sound speeds on the contact damping. For small wave numbers, the dispersion relations and sound speeds of acoustic modes are quite insensitive to the damping. However, a small dip in the phase speed of the transverse mode decreases as the viscous force in normal direction increases. In addition, the dispersion relation of the rotational mode differs qualitatively from the theoretical prediction for granular crystals. Therefore, disordered configurations with energy dissipation play a prominent role in sound properties of granular materials. Furthermore, we report how attenuation coefficients depend on the contact damping and quantify how they differ from the prediction of lattice theory. These improved relations, based on our numerical results, can in future be compared to advanced theories and experiments.
AB - We investigate numerically the sound properties of disordered dense granular packings in two dimensions. Employing linear equations of motion and excluding contact changes from our simulations, we demonstrate time evolution of sinusoidal standing waves of granular disks. We varied the strength of normal and tangential viscous forces between the disks in contact to explore the dependence of sound characteristics such as dispersion relations, attenuation coefficients, and sound speeds on the contact damping. For small wave numbers, the dispersion relations and sound speeds of acoustic modes are quite insensitive to the damping. However, a small dip in the phase speed of the transverse mode decreases as the viscous force in normal direction increases. In addition, the dispersion relation of the rotational mode differs qualitatively from the theoretical prediction for granular crystals. Therefore, disordered configurations with energy dissipation play a prominent role in sound properties of granular materials. Furthermore, we report how attenuation coefficients depend on the contact damping and quantify how they differ from the prediction of lattice theory. These improved relations, based on our numerical results, can in future be compared to advanced theories and experiments.
U2 - 10.3389/fphy.2023.1192270
DO - 10.3389/fphy.2023.1192270
M3 - Article
SN - 2296-424X
VL - 11
SP - 1
EP - 10
JO - Frontiers in Physics
JF - Frontiers in Physics
M1 - 1192270
ER -