Large Eddy Simulation of Internal Boundary Layers Created by a Change in Surface Roughness.
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| Title: | Large Eddy Simulation of Internal Boundary Layers Created by a Change in Surface Roughness. |
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| Authors: | Glendening, John W., Lin, Ching-Long |
| Source: | Journal of the Atmospheric Sciences. 5/15/2002, Vol. 59 Issue 10, p1697. 15p. 22 Graphs. |
| Subjects: | Reynolds stress, Atmospheric boundary layer, Turbulence |
| Abstract: | Turbulence in a γ-mesoscale internal boundary layer (IBL) formed by a discontinuous change in surface roughness has been investigated using a large eddy simulation (LES) model to explicitly treat turbulent transport. Two cases are examined: a rough-to-smooth transition and a smooth-to-rough transition. IBL heights are identified using two absolute criteria, one in terms of horizontal stress variation and the other in terms of vertical stress variation, and the ratio of these two heights is found to be approximately constant with fetch. The IBL growth rate with fetch is essentially the same for both transitions, which is here interpreted as reflecting self-similarity of the IBL at relatively large fetches. Parameterization of IBL growth in terms of turbulent intensity is successful when the average turbulent intensity in the IBL is employed but not if the turbulent intensity at the IBL top is utilized. The effective eddy mixing length for longitudinal velocity does not experience strong variations in the vicinity of the surface discontinuity when parameterized in terms of the local turbulent kinetic energy (TKE), but the effective mixing length is somewhat larger over the smoother surface as a result of pressure gradients induced by the horizontally inhomogeneous flow. The TKE dissipation length scale is roughly equal to the mixing length scale for longitudinal velocity, so stress and TKE are strongly coupled above the surface layer. The “quality” of turbulence, evaluated by turbulent skewness and kurtosis, indicates that turbulence above and below the identified IBL height is associated with the upstream and underlying surfaces, respectively, demonstrating that this height is a physically relevant length scale. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of the Atmospheric Sciences is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 6533355 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Large Eddy Simulation of Internal Boundary Layers Created by a Change in Surface Roughness. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Glendening%2C+John+W%2E%22">Glendening, John W.</searchLink><br /><searchLink fieldCode="AR" term="%22Lin%2C+Ching-Long%22">Lin, Ching-Long</searchLink> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+the+Atmospheric+Sciences%22">Journal of the Atmospheric Sciences</searchLink>. 5/15/2002, Vol. 59 Issue 10, p1697. 15p. 22 Graphs. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Reynolds+stress%22">Reynolds stress</searchLink><br /><searchLink fieldCode="DE" term="%22Atmospheric+boundary+layer%22">Atmospheric boundary layer</searchLink><br /><searchLink fieldCode="DE" term="%22Turbulence%22">Turbulence</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Turbulence in a γ-mesoscale internal boundary layer (IBL) formed by a discontinuous change in surface roughness has been investigated using a large eddy simulation (LES) model to explicitly treat turbulent transport. Two cases are examined: a rough-to-smooth transition and a smooth-to-rough transition. IBL heights are identified using two absolute criteria, one in terms of horizontal stress variation and the other in terms of vertical stress variation, and the ratio of these two heights is found to be approximately constant with fetch. The IBL growth rate with fetch is essentially the same for both transitions, which is here interpreted as reflecting self-similarity of the IBL at relatively large fetches. Parameterization of IBL growth in terms of turbulent intensity is successful when the average turbulent intensity in the IBL is employed but not if the turbulent intensity at the IBL top is utilized. The effective eddy mixing length for longitudinal velocity does not experience strong variations in the vicinity of the surface discontinuity when parameterized in terms of the local turbulent kinetic energy (TKE), but the effective mixing length is somewhat larger over the smoother surface as a result of pressure gradients induced by the horizontally inhomogeneous flow. The TKE dissipation length scale is roughly equal to the mixing length scale for longitudinal velocity, so stress and TKE are strongly coupled above the surface layer. The “quality” of turbulence, evaluated by turbulent skewness and kurtosis, indicates that turbulence above and below the identified IBL height is associated with the upstream and underlying surfaces, respectively, demonstrating that this height is a physically relevant length scale. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of the Atmospheric Sciences is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1175/1520-0469(2002)059<1697:LESOIB>2.0.CO;2 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 15 StartPage: 1697 Subjects: – SubjectFull: Reynolds stress Type: general – SubjectFull: Atmospheric boundary layer Type: general – SubjectFull: Turbulence Type: general Titles: – TitleFull: Large Eddy Simulation of Internal Boundary Layers Created by a Change in Surface Roughness. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Glendening, John W. – PersonEntity: Name: NameFull: Lin, Ching-Long IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 05 Text: 5/15/2002 Type: published Y: 2002 Identifiers: – Type: issn-print Value: 00224928 Numbering: – Type: volume Value: 59 – Type: issue Value: 10 Titles: – TitleFull: Journal of the Atmospheric Sciences Type: main |
| ResultId | 1 |
