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Molecular dynamics studies of anomalous transport in rarefied gas flows

Dongari, Nishanth and Zhang, Yonghao and Reese, Jason (2010) Molecular dynamics studies of anomalous transport in rarefied gas flows. In: 2nd European Conference on Microfluidics, 2010-12-08 - 2010-12-10, Toulouse,.

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    Abstract

    We investigate the thermodynamically non-equilibrium gas dynamics by measuring molecular free path distribution functions, inter-molecular collision rates and wall dependent mean free path (MFP) profiles using the molecular dynamics (MD) method. The simulations cover a wide range of fluid densities for single-wall case, parallel walls cases and a cube with all periodic walls. The simulations are validated by deducing the theoretical unconfined MFP values at standardpressure and temperature conditions. The free path MD measurements of individual molecules convey that conventional exponential distribution function is not valid under rarefied conditions and molecules follow L´evy type flights, irrespective of the presence of a wall. MFP profile measurements for confined planar surfaces in the transition flow regime show sharp gradients close to the wall, while theoretical models predict shallower gradients. As gas transport properties can be related to the MFP through kinetic theory, our MD data may help to modify the constitutive relationships, which may then be fed into the Navier-Stokes equations for better effective modeling of micro gas flows in the transition flow regime.

    Item type: Conference or Workshop Item (Paper)
    ID code: 32132
    Notes: Published on CD-ROM
    Keywords: rarefied gas flows, free path distribution, L´evy flights, mean free path , molecular dynamics, Mechanical engineering and machinery
    Subjects: Technology > Mechanical engineering and machinery
    Department: Faculty of Engineering > Mechanical and Aerospace Engineering
    Related URLs:
    Depositing user: Pure Administrator
    Date Deposited: 13 Jul 2011 10:07
    Last modified: 17 Dec 2013 16:05
    URI: http://strathprints.strath.ac.uk/id/eprint/32132

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