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Estimation of tangential momentum ac...

Finger, George Wayne.

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Estimation of tangential momentum accommodation coefficient using molecular dynamics simulation.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Estimation of tangential momentum accommodation coefficient using molecular dynamics simulation./
Author:	Finger, George Wayne.
Description:	164 p.
Notes:	Source: Dissertation Abstracts International, Volume: 66-10, Section: B, page: 5639.
Contained By:	Dissertation Abstracts International66-10B.
Subject:	Engineering, Mechanical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3193474
ISBN:	9780542361821

Estimation of tangential momentum accommodation coefficient using molecular dynamics simulation.
Finger, George Wayne.

Estimation of tangential momentum accommodation coefficient using molecular dynamics simulation. - 164 p.

Source: Dissertation Abstracts International, Volume: 66-10, Section: B, page: 5639.

Thesis (Ph.D.)--University of Central Florida, 2005.

The Tangential Momentum Accommodation Coefficient (TMAC) is used to improve the accuracy of fluid flow calculations in the slip flow regime. Under such conditions the continuum assumption that a fluid velocity at a solid surface is equal to the surface velocity is inaccurate because relatively significant fluid "slip" occurs at the surface. In this work, Molecular Dynamics techniques are used to study the impacts of individual gas atoms upon solid surfaces to understand how approach velocity, crystal geometry and interatomic forces affect the scattering of the gas atoms, specifically from the perspective of tangential momentum.

ISBN: 9780542361821Subjects--Topical Terms:

783786
Engineering, Mechanical.

Estimation of tangential momentum accommodation coefficient using molecular dynamics simulation.
LDR:03184nmm 2200313 4500 001 1824930
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020 $a 9780542361821
035 $a (UnM)AAI3193474
035 $a AAI3193474
040 $a UnM $c UnM
100 1 $a Finger, George Wayne. $3 1913961
245 1 0 $a Estimation of tangential momentum accommodation coefficient using molecular dynamics simulation.
300 $a 164 p.
500 $a Source: Dissertation Abstracts International, Volume: 66-10, Section: B, page: 5639.
500 $a Major Professor: Jayanta Kapat.
502 $a Thesis (Ph.D.)--University of Central Florida, 2005.
520 $a The Tangential Momentum Accommodation Coefficient (TMAC) is used to improve the accuracy of fluid flow calculations in the slip flow regime. Under such conditions the continuum assumption that a fluid velocity at a solid surface is equal to the surface velocity is inaccurate because relatively significant fluid "slip" occurs at the surface. In this work, Molecular Dynamics techniques are used to study the impacts of individual gas atoms upon solid surfaces to understand how approach velocity, crystal geometry and interatomic forces affect the scattering of the gas atoms, specifically from the perspective of tangential momentum.
520 $a The gas - solid impacts were modeled using Lennard Jones potentials. Solid surfaces were modeled with approximately 3 atoms wide by 3 atoms deep by 40 or more atoms long. The crystal surface was modeled as a Face Centered Cubic (100). The gas was modeled as individual free gas atoms. Gas approach angles were varied from 10° to 70° from normal. Gas speed was either specified directly or by way of a ratio relationship with the Lennard-Jones energy potential (Energy Ratio). For each impact the initial and final tangential momenta were determined and after a series of many impacts, a value of TMAC was calculated for those conditions.
520 $a The modeling was validated with available experimental data for He gas atoms at 1770 m/s impacting Cu over angles ranging from 10° to 70°. The model agreed within 3% of the experimental values and correctly predicted that the coefficient changes with angle of approach.
520 $a Molecular Dynamics results estimate TMAC values from a high of 1.2 to a low of 0.25, generally estimating a higher coefficient at the smaller angles. TMAC values above 1.0 indicate backscattering, which has been experimentally observed in numerous instances. Increasing the Energy Ratio above a value of 5 tends to decrease the coefficient at all angles. Adsorbed layers atop a surface influence the coefficient similar to their Energy Ratio. The results provide encouragement to develop the model further, so as to be able in the future to evaluate TMAC for gas flows with Maxwell temperature distributions involving numerous impact angles simultaneously.
590 $a School code: 0705.
650 4 $a Engineering, Mechanical. $3 783786
650 4 $a Physics, Molecular. $3 1018648
690 $a 0548
690 $a 0609
710 2 0 $a University of Central Florida. $3 1018467
773 0 $t Dissertation Abstracts International $g 66-10B.
790 1 0 $a Kapat, Jayanta, $e advisor
790 $a 0705
791 $a Ph.D.
792 $a 2005
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3193474