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Entropy Generation in the Viscous Layer ofa Turbulent Channel Flow. 5th International Symposium on Turbulence, Heat and Mass Transfer (THMT-5).

DE2007911191

Publication Date	2006
Personal Author	McEligot, D. M.; Walsh, E. J.; Laurien, E.
Page Count	13
Abstract	The local (pointwise) entropy generation rate per unit volume S is a key to improving many energy processes and applications. Entropy generation due to friction occurs from viscous dissipation of mean-flow kinetic energy (called 'direct dissipation') and dissipation of turbulent kinetic energy into thermal energy ('indirect' or turbulent dissipation). The objective of the present study is to compare two approaches for the prediction of S for the viscous layer in near asymptotic (high Reynolds number) turbulent flows. By employing available direct numerical simulations (DNS) it was found that about two-thirds of the entropy generation occurs in this layer. A popular approximate approach does not agree with the result from the more exact evaluation of S but its integral falls within about four per cent at the edge of the viscous layer.
Keywords	Entropy Turbulence Channel flow Friction Kinetic energy Turbulent flow Reynolds number Dissipation factor Integrals Numerical analysis Simulation Evaluation Meetings Entropy generation
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Argonne National Lab., Idaho Falls, ID.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200801

Entropy Generation in the Viscous Layer ofa Turbulent Channel Flow. 5th International Symposium on Turbulence, Heat and Mass Transfer (THMT-5).

Entropy Generation in the Viscous Layer ofa Turbulent Channel Flow. 5th International Symposium on Turbulence, Heat and Mass Transfer (THMT-5).
DE2007911191

Publication Date	2006
Personal Author	McEligot, D. M.; Walsh, E. J.; Laurien, E.
Page Count	13
Abstract	The local (pointwise) entropy generation rate per unit volume S is a key to improving many energy processes and applications. Entropy generation due to friction occurs from viscous dissipation of mean-flow kinetic energy (called 'direct dissipation') and dissipation of turbulent kinetic energy into thermal energy ('indirect' or turbulent dissipation). The objective of the present study is to compare two approaches for the prediction of S for the viscous layer in near asymptotic (high Reynolds number) turbulent flows. By employing available direct numerical simulations (DNS) it was found that about two-thirds of the entropy generation occurs in this layer. A popular approximate approach does not agree with the result from the more exact evaluation of S but its integral falls within about four per cent at the edge of the viscous layer.
Keywords	Entropy Turbulence Channel flow Friction Kinetic energy Turbulent flow Reynolds number Dissipation factor Integrals Numerical analysis Simulation Evaluation Meetings Entropy generation
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Argonne National Lab., Idaho Falls, ID.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200801