Documents disponibles écrits par cet auteur

Large Eddy simulation of turbulent axial flow along an array of rods / F. Abbasian in Transactions of the ASME . Journal of fluids engineering, Vol. 132 N° 2 (Fevrier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 132 N° 2 (Fevrier 2010) . - 11 p. Titre : Large Eddy simulation of turbulent axial flow along an array of rods Type de document : texte imprimé Auteurs : F. Abbasian, Auteur ; S. D. Yu, Auteur ; J. Cao, Auteur Année de publication : 2010 Article en page(s) : 11 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : flow  (dynamics);  turbulence;  axial  flow;  rods;  large  eddy  simulation Résumé : Large eddy simulation (LES) is employed in this paper to model the axial flow along a circular array of rods with a focus on anisotropic large-scale turbulence. The circular array consists of four whole rods and eight half rods, with a pitch-to-diameter ratio of 1.08. A dynamic Smagorinsky model with SIMPLE coupling method and a bounded central difference scheme are used to reduce numerical errors. The high demands for computations of the three-dimensional turbulent flows are afforded through parallel processing and utilization of 20 processors. The numerical results obtained using LES are compared with independent experimental data available in the literature; good agreement is achieved. The LES model was developed to accurately predict (i) the dependence of turbulence intensity and dominant frequency on the gap size and (ii) the turbulence structure in different directions. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27408 [...] [article] Large Eddy simulation of turbulent axial flow along an array of rods [texte imprimé] / F. Abbasian, Auteur ; S. D. Yu, Auteur ; J. Cao, Auteur . - 2010 . - 11 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 132 N° 2 (Fevrier 2010) . - 11 p. Mots-clés : flow  (dynamics);  turbulence;  axial  flow;  rods;  large  eddy  simulation Résumé : Large eddy simulation (LES) is employed in this paper to model the axial flow along a circular array of rods with a focus on anisotropic large-scale turbulence. The circular array consists of four whole rods and eight half rods, with a pitch-to-diameter ratio of 1.08. A dynamic Smagorinsky model with SIMPLE coupling method and a bounded central difference scheme are used to reduce numerical errors. The high demands for computations of the three-dimensional turbulent flows are afforded through parallel processing and utilization of 20 processors. The numerical results obtained using LES are compared with independent experimental data available in the literature; good agreement is achieved. The LES model was developed to accurately predict (i) the dependence of turbulence intensity and dominant frequency on the gap size and (ii) the turbulence structure in different directions. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27408 [...]

Numerical and experimental studies of oscillatory airflows induced by rotation of a grass-cutting blade / F. Abbasian in Transactions of the ASME . Journal of fluids engineering, Vol. 130 N° 3 (Mars 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 130 N° 3 (Mars 2008) . - 8 p. Titre : Numerical and experimental studies of oscillatory airflows induced by rotation of a grass-cutting blade Type de document : texte imprimé Auteurs : F. Abbasian, Auteur ; J. Cao, Auteur ; S. D. Yu, Auteur Année de publication : 2009 Article en page(s) : 8 p. Note générale : Fluids engineering Langues : Anglais (eng) Mots-clés : Three-dimensional  oscillatory  airflows;  cylindrical  chamber;  Navier–Stokes  equations Résumé : Three-dimensional oscillatory airflows induced by a rotating grass-cutting blade in a cylindrical chamber are studied experimentally and numerically in this paper. Experimental pressure results are obtained using a sound pressure transducer and a data acquisition system. The measured pressure data contain background noise and high-frequency sound signals due to the blade vibrations. The background noise is separately measured; its effect on the signal is determined from a spectral subtraction algorithm. A time-accurate finite volume numerical solution to the three-dimensional incompressible unsteady Navier–Stokes equations is also sought using the sliding frame technique and the unstructured tetrahedral mesh. Convergence studies are conducted using various combinations of mesh sizes and time increments to ensure the stability of the numerical scheme. The experimental and numerical pressure results are in good agreement. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27301 [...] [article] Numerical and experimental studies of oscillatory airflows induced by rotation of a grass-cutting blade [texte imprimé] / F. Abbasian, Auteur ; J. Cao, Auteur ; S. D. Yu, Auteur . - 2009 . - 8 p. Fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 130 N° 3 (Mars 2008) . - 8 p. Mots-clés : Three-dimensional  oscillatory  airflows;  cylindrical  chamber;  Navier–Stokes  equations Résumé : Three-dimensional oscillatory airflows induced by a rotating grass-cutting blade in a cylindrical chamber are studied experimentally and numerically in this paper. Experimental pressure results are obtained using a sound pressure transducer and a data acquisition system. The measured pressure data contain background noise and high-frequency sound signals due to the blade vibrations. The background noise is separately measured; its effect on the signal is determined from a spectral subtraction algorithm. A time-accurate finite volume numerical solution to the three-dimensional incompressible unsteady Navier–Stokes equations is also sought using the sliding frame technique and the unstructured tetrahedral mesh. Convergence studies are conducted using various combinations of mesh sizes and time increments to ensure the stability of the numerical scheme. The experimental and numerical pressure results are in good agreement. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27301 [...]