POD Analysis of Entropy Generation in a Laminar Separation Boundary Layer
Separation of laminar boundary layer is a great source of loss in energy and power machinery. This paper investigates the entropy generation of the boundary layer on the flat plate with pressure gradient. The velocity of the flow field is measured by a high resolution and time related particle image...
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| Format: | Article |
| Language: | English |
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MDPI AG
2018-11-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/11/11/3003 |
| _version_ | 1811303342747418624 |
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| author | Chao Jin Hongwei Ma |
| author_facet | Chao Jin Hongwei Ma |
| author_sort | Chao Jin |
| collection | DOAJ |
| description | Separation of laminar boundary layer is a great source of loss in energy and power machinery. This paper investigates the entropy generation of the boundary layer on the flat plate with pressure gradient. The velocity of the flow field is measured by a high resolution and time related particle image velocimetry (PIV) system. A method to estimate the entropy generation of each mode extracted by proper orthogonal decomposition (POD) is introduced. The entropy generation of each POD mode caused by mean viscous, Reynolds normal stress, Reynolds sheer stress, and energy flux is analyzed. The first order mode of the mean viscous term contributes almost 100% of the total entropy generation. The first three order modes of the Reynolds sheer stress term contribute less than 10% of the total entropy generation in the fore part of the separation bubble, while it reaches to more than 95% in the rear part of the separation bubble. It indicates that the more unsteady that the flow is, the higher contribution rate of the Reynolds sheer stress term makes. The energy flux term plays an important role in the turbulent kinetic energy balance in the transition region. |
| first_indexed | 2024-04-13T07:45:15Z |
| format | Article |
| id | doaj.art-eac241181f8b4bb8b2fb8f32f6b3b102 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-13T07:45:15Z |
| publishDate | 2018-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-eac241181f8b4bb8b2fb8f32f6b3b1022022-12-22T02:55:42ZengMDPI AGEnergies1996-10732018-11-011111300310.3390/en11113003en11113003POD Analysis of Entropy Generation in a Laminar Separation Boundary LayerChao Jin0Hongwei Ma1School of Energy and Power Engineering, Beihang University, Beijing 100191, ChinaSchool of Energy and Power Engineering, Beihang University, Beijing 100191, ChinaSeparation of laminar boundary layer is a great source of loss in energy and power machinery. This paper investigates the entropy generation of the boundary layer on the flat plate with pressure gradient. The velocity of the flow field is measured by a high resolution and time related particle image velocimetry (PIV) system. A method to estimate the entropy generation of each mode extracted by proper orthogonal decomposition (POD) is introduced. The entropy generation of each POD mode caused by mean viscous, Reynolds normal stress, Reynolds sheer stress, and energy flux is analyzed. The first order mode of the mean viscous term contributes almost 100% of the total entropy generation. The first three order modes of the Reynolds sheer stress term contribute less than 10% of the total entropy generation in the fore part of the separation bubble, while it reaches to more than 95% in the rear part of the separation bubble. It indicates that the more unsteady that the flow is, the higher contribution rate of the Reynolds sheer stress term makes. The energy flux term plays an important role in the turbulent kinetic energy balance in the transition region.https://www.mdpi.com/1996-1073/11/11/3003PODentropy generationboundary layerlaminar separation bubble |
| spellingShingle | Chao Jin Hongwei Ma POD Analysis of Entropy Generation in a Laminar Separation Boundary Layer Energies POD entropy generation boundary layer laminar separation bubble |
| title | POD Analysis of Entropy Generation in a Laminar Separation Boundary Layer |
| title_full | POD Analysis of Entropy Generation in a Laminar Separation Boundary Layer |
| title_fullStr | POD Analysis of Entropy Generation in a Laminar Separation Boundary Layer |
| title_full_unstemmed | POD Analysis of Entropy Generation in a Laminar Separation Boundary Layer |
| title_short | POD Analysis of Entropy Generation in a Laminar Separation Boundary Layer |
| title_sort | pod analysis of entropy generation in a laminar separation boundary layer |
| topic | POD entropy generation boundary layer laminar separation bubble |
| url | https://www.mdpi.com/1996-1073/11/11/3003 |
| work_keys_str_mv | AT chaojin podanalysisofentropygenerationinalaminarseparationboundarylayer AT hongweima podanalysisofentropygenerationinalaminarseparationboundarylayer |