Large eddy simulation of aircraft at affordable cost: a milestone in computational fluid dynamics
While there have been numerous applications of large eddy simulations (LES) to complex flows, their application to practical engineering configurations, such as full aircraft models, have been limited to date. Recently, however, advances in rapid, high quality mesh generation, low-dissipation numeri...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2021-01-01
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| Series: | Flow |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S2633425921000179/type/journal_article |
| _version_ | 1811156308092518400 |
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| author | Konrad A. Goc Oriol Lehmkuhl George Ilhwan Park Sanjeeb T. Bose Parviz Moin |
| author_facet | Konrad A. Goc Oriol Lehmkuhl George Ilhwan Park Sanjeeb T. Bose Parviz Moin |
| author_sort | Konrad A. Goc |
| collection | DOAJ |
| description | While there have been numerous applications of large eddy simulations (LES) to complex flows, their application to practical engineering configurations, such as full aircraft models, have been limited to date. Recently, however, advances in rapid, high quality mesh generation, low-dissipation numerical schemes and physics-based subgrid-scale and wall models have led to, for the first time, accurate simulations of a realistic aircraft in landing configuration (the Japanese Aerospace Exploration Agency Standard Model) in less than a day of turnaround time with modest resource requirements. In this paper, a systematic study of the predictive capability of LES across a range of angles of attack (including maximum lift and post-stall regimes), the robustness of the predictions to grid resolution and the incorporation of wind tunnel effects is carried out. Integrated engineering quantities of interest, such as lift, drag and pitching moment will be compared with experimental data, while sectional pressure forces will be used to corroborate the accuracy of the integrated quantities. Good agreement with experimental $C_L$ data is obtained across the lift curve with the coefficient of lift at maximum lift, $C_{L,max}$, consistently being predicted to within five lift counts of the experimental value. The grid point requirements to achieve this level of accuracy are reduced compared with recent estimates (even for wall modelled LES), with the solutions showing systematic improvement upon grid refinement, with the exception of the solution at the lowest angles of attack, which will be discussed later in the text. Simulations that include the wind tunnel walls and aircraft body mounting system are able to replicate important features of the flow field noted in the experiment that are absent from free air calculations of the same geometry, namely, the onset of inboard flow separation in the post-stall regime. Turnaround times of the order of a day are made possible in part by algorithmic advances made to leverage graphical processing units. The results presented herein suggest that this combined approach (meshing, numerical algorithms, modelling, efficient computer implementation) is on the threshold of readiness for industrial use in aeronautical design. |
| first_indexed | 2024-04-10T04:49:23Z |
| format | Article |
| id | doaj.art-7778cba92f194d62bbf3f00b08842bd6 |
| institution | Directory Open Access Journal |
| issn | 2633-4259 |
| language | English |
| last_indexed | 2024-04-10T04:49:23Z |
| publishDate | 2021-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Flow |
| spelling | doaj.art-7778cba92f194d62bbf3f00b08842bd62023-03-09T12:34:16ZengCambridge University PressFlow2633-42592021-01-01110.1017/flo.2021.17Large eddy simulation of aircraft at affordable cost: a milestone in computational fluid dynamicsKonrad A. Goc0https://orcid.org/0000-0002-8791-4969Oriol Lehmkuhl1George Ilhwan Park2https://orcid.org/0000-0002-8242-8515Sanjeeb T. Bose3Parviz Moin4https://orcid.org/0000-0002-0491-7065Center for Turbulence Research, Stanford University, Stanford, CA 94305, USABarcelona Supercomputing Center, Barcelona 08034, SpainDepartment of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USACascade Technologies, Inc., Palo Alto, CA 94303, USA Institute for Computational & Mathematical Engineering, Stanford University, Stanford, CA 94305, USACenter for Turbulence Research, Stanford University, Stanford, CA 94305, USAWhile there have been numerous applications of large eddy simulations (LES) to complex flows, their application to practical engineering configurations, such as full aircraft models, have been limited to date. Recently, however, advances in rapid, high quality mesh generation, low-dissipation numerical schemes and physics-based subgrid-scale and wall models have led to, for the first time, accurate simulations of a realistic aircraft in landing configuration (the Japanese Aerospace Exploration Agency Standard Model) in less than a day of turnaround time with modest resource requirements. In this paper, a systematic study of the predictive capability of LES across a range of angles of attack (including maximum lift and post-stall regimes), the robustness of the predictions to grid resolution and the incorporation of wind tunnel effects is carried out. Integrated engineering quantities of interest, such as lift, drag and pitching moment will be compared with experimental data, while sectional pressure forces will be used to corroborate the accuracy of the integrated quantities. Good agreement with experimental $C_L$ data is obtained across the lift curve with the coefficient of lift at maximum lift, $C_{L,max}$, consistently being predicted to within five lift counts of the experimental value. The grid point requirements to achieve this level of accuracy are reduced compared with recent estimates (even for wall modelled LES), with the solutions showing systematic improvement upon grid refinement, with the exception of the solution at the lowest angles of attack, which will be discussed later in the text. Simulations that include the wind tunnel walls and aircraft body mounting system are able to replicate important features of the flow field noted in the experiment that are absent from free air calculations of the same geometry, namely, the onset of inboard flow separation in the post-stall regime. Turnaround times of the order of a day are made possible in part by algorithmic advances made to leverage graphical processing units. The results presented herein suggest that this combined approach (meshing, numerical algorithms, modelling, efficient computer implementation) is on the threshold of readiness for industrial use in aeronautical design.https://www.cambridge.org/core/product/identifier/S2633425921000179/type/journal_articleLarge eddy simulationAerodynamicsSeparated flowsPrediction of maximum liftFull aircraft simulation |
| spellingShingle | Konrad A. Goc Oriol Lehmkuhl George Ilhwan Park Sanjeeb T. Bose Parviz Moin Large eddy simulation of aircraft at affordable cost: a milestone in computational fluid dynamics Flow Large eddy simulation Aerodynamics Separated flows Prediction of maximum lift Full aircraft simulation |
| title | Large eddy simulation of aircraft at affordable cost: a milestone in computational fluid dynamics |
| title_full | Large eddy simulation of aircraft at affordable cost: a milestone in computational fluid dynamics |
| title_fullStr | Large eddy simulation of aircraft at affordable cost: a milestone in computational fluid dynamics |
| title_full_unstemmed | Large eddy simulation of aircraft at affordable cost: a milestone in computational fluid dynamics |
| title_short | Large eddy simulation of aircraft at affordable cost: a milestone in computational fluid dynamics |
| title_sort | large eddy simulation of aircraft at affordable cost a milestone in computational fluid dynamics |
| topic | Large eddy simulation Aerodynamics Separated flows Prediction of maximum lift Full aircraft simulation |
| url | https://www.cambridge.org/core/product/identifier/S2633425921000179/type/journal_article |
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