Granular motor in the non-Brownian limit

Loreto Alejandra Oyarte Galvez, Roger M. van der Meer

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)

Abstract

In this work we experimentally study a granular rotor which is similar to the famous Smoluchowski–Feynman device and which consists of a rotor with four vanes immersed in a granular gas. Each side of the vanes can be composed of two different materials, creating a rotational asymmetry and turning the rotor into a ratchet. When the granular temperature is high, the rotor is in movement all the time, and its angular velocity distribution is well described by the Brownian limit discussed in previous works. When the granular temperature is lowered considerably we enter the so-called single kick limit, where collisions occur rarely and the unavoidable external friction causes the rotor to be at rest for most of the time. We find that the existing models are not capable of adequately describing the experimentally observed distribution in this limit. We trace back this discrepancy to the non-constancy of the deceleration due to external friction and show that incorporating this effect into the existing models leads to full agreement with our experiments. Subsequently, we extend this model to describe the angular velocity distribution of the rotor for any temperature of the gas, and obtain a very good agreement between the model and experimental data.
Original languageEnglish
Pages (from-to)043206-
Number of pages23
JournalJournal of statistical mechanics : theory and experiment
Volume13
DOIs
Publication statusPublished - 2016

Fingerprint

Rotor
rotors
vanes
Velocity Distribution
Angular velocity
angular velocity
Friction
friction
velocity distribution
Granular Gases
Ratchet
deceleration
gases
Model
Asymmetry
Discrepancy
Collision
Trace
asymmetry
Experimental Data

Keywords

  • METIS-321430
  • IR-103932

Cite this

@article{1ec1b882ce32476fa19d371035feaa25,
title = "Granular motor in the non-Brownian limit",
abstract = "In this work we experimentally study a granular rotor which is similar to the famous Smoluchowski–Feynman device and which consists of a rotor with four vanes immersed in a granular gas. Each side of the vanes can be composed of two different materials, creating a rotational asymmetry and turning the rotor into a ratchet. When the granular temperature is high, the rotor is in movement all the time, and its angular velocity distribution is well described by the Brownian limit discussed in previous works. When the granular temperature is lowered considerably we enter the so-called single kick limit, where collisions occur rarely and the unavoidable external friction causes the rotor to be at rest for most of the time. We find that the existing models are not capable of adequately describing the experimentally observed distribution in this limit. We trace back this discrepancy to the non-constancy of the deceleration due to external friction and show that incorporating this effect into the existing models leads to full agreement with our experiments. Subsequently, we extend this model to describe the angular velocity distribution of the rotor for any temperature of the gas, and obtain a very good agreement between the model and experimental data.",
keywords = "METIS-321430, IR-103932",
author = "{Oyarte Galvez}, {Loreto Alejandra} and {van der Meer}, {Roger M.}",
year = "2016",
doi = "10.1088/1742-5468/2016/04/043206",
language = "English",
volume = "13",
pages = "043206--",
journal = "Journal of statistical mechanics : theory and experiment",
issn = "1742-5468",
publisher = "IOP Publishing Ltd.",

}

Granular motor in the non-Brownian limit. / Oyarte Galvez, Loreto Alejandra; van der Meer, Roger M.

In: Journal of statistical mechanics : theory and experiment, Vol. 13, 2016, p. 043206-.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Granular motor in the non-Brownian limit

AU - Oyarte Galvez, Loreto Alejandra

AU - van der Meer, Roger M.

PY - 2016

Y1 - 2016

N2 - In this work we experimentally study a granular rotor which is similar to the famous Smoluchowski–Feynman device and which consists of a rotor with four vanes immersed in a granular gas. Each side of the vanes can be composed of two different materials, creating a rotational asymmetry and turning the rotor into a ratchet. When the granular temperature is high, the rotor is in movement all the time, and its angular velocity distribution is well described by the Brownian limit discussed in previous works. When the granular temperature is lowered considerably we enter the so-called single kick limit, where collisions occur rarely and the unavoidable external friction causes the rotor to be at rest for most of the time. We find that the existing models are not capable of adequately describing the experimentally observed distribution in this limit. We trace back this discrepancy to the non-constancy of the deceleration due to external friction and show that incorporating this effect into the existing models leads to full agreement with our experiments. Subsequently, we extend this model to describe the angular velocity distribution of the rotor for any temperature of the gas, and obtain a very good agreement between the model and experimental data.

AB - In this work we experimentally study a granular rotor which is similar to the famous Smoluchowski–Feynman device and which consists of a rotor with four vanes immersed in a granular gas. Each side of the vanes can be composed of two different materials, creating a rotational asymmetry and turning the rotor into a ratchet. When the granular temperature is high, the rotor is in movement all the time, and its angular velocity distribution is well described by the Brownian limit discussed in previous works. When the granular temperature is lowered considerably we enter the so-called single kick limit, where collisions occur rarely and the unavoidable external friction causes the rotor to be at rest for most of the time. We find that the existing models are not capable of adequately describing the experimentally observed distribution in this limit. We trace back this discrepancy to the non-constancy of the deceleration due to external friction and show that incorporating this effect into the existing models leads to full agreement with our experiments. Subsequently, we extend this model to describe the angular velocity distribution of the rotor for any temperature of the gas, and obtain a very good agreement between the model and experimental data.

KW - METIS-321430

KW - IR-103932

U2 - 10.1088/1742-5468/2016/04/043206

DO - 10.1088/1742-5468/2016/04/043206

M3 - Article

VL - 13

SP - 043206-

JO - Journal of statistical mechanics : theory and experiment

JF - Journal of statistical mechanics : theory and experiment

SN - 1742-5468

ER -