An immersed boundary method for practical simulations of high-Reynolds number flows by k-ε RANS models
A combustion simulation software tool, “HINOCA”, has been developed for automotive engine analysis. HINOCA is based on fully compressible Navier-Stokes equations, which are Reynolds-averaged (RANS) or spatially-filtered (LES), and employs the Cartesian grid and immersed boundary (IB) methods to redu...
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| Format: | Article |
| Language: | English |
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The Japan Society of Mechanical Engineers
2021-01-01
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| Series: | Journal of Fluid Science and Technology |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/jfst/16/1/16_2021jfst0007/_pdf/-char/en |
| _version_ | 1818753220338515968 |
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| author | Hiroki YAO Taisuke NAMBU Yasuhiro MIZOBUCHI |
| author_facet | Hiroki YAO Taisuke NAMBU Yasuhiro MIZOBUCHI |
| author_sort | Hiroki YAO |
| collection | DOAJ |
| description | A combustion simulation software tool, “HINOCA”, has been developed for automotive engine analysis. HINOCA is based on fully compressible Navier-Stokes equations, which are Reynolds-averaged (RANS) or spatially-filtered (LES), and employs the Cartesian grid and immersed boundary (IB) methods to reduce the mesh generation cost. In the present paper, focusing on flow simulations using k-ε models, a robust and reliable IB method coupled with wall functions is proposed. One major aspect of the method is that different IB cell information is employed for inviscid and viscous flux evaluations at fluid-IB cell interfaces. To improve the evaluation of wall shear stress, the shear stresses on the boundaries of an IB cell are transformed into a body force acting on the adjacent fluid cell. The computational method for ε-equation and the source terms of the k-equation near IB cells are modified so that the development of the turbulent boundary layer on a flat plate is well reproduced. The effects of these modifications are validated by the 2D Zero Pressure Gradient Flat Plate problem. To improve the mass conservation property of the IB method, multiple geometric parameters are defined for IB cells; that is, different image point information is immersed on IB cell centers for evaluating the inviscid flux on each cell interface. Evaluation with the Steady State Flow Bench problem shows that the proposed method drastically improves the mass conservation property of simulations and is able with a coarse mesh to reproduce flow structures obtained by LES with a much finer mesh. |
| first_indexed | 2024-12-18T05:03:54Z |
| format | Article |
| id | doaj.art-ea85aa8bc2074a20958557cd49782543 |
| institution | Directory Open Access Journal |
| issn | 1880-5558 |
| language | English |
| last_indexed | 2024-12-18T05:03:54Z |
| publishDate | 2021-01-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Journal of Fluid Science and Technology |
| spelling | doaj.art-ea85aa8bc2074a20958557cd497825432022-12-21T21:20:04ZengThe Japan Society of Mechanical EngineersJournal of Fluid Science and Technology1880-55582021-01-01161JFST0007JFST000710.1299/jfst.2021jfst0007jfstAn immersed boundary method for practical simulations of high-Reynolds number flows by k-ε RANS modelsHiroki YAO0Taisuke NAMBU1Yasuhiro MIZOBUCHI2Ryoyu Systems Co., Ltd.Numerical Simulation Research Unit, Aeronautical Technology Directorate, Japan Aerospace Exploration AgencyNumerical Simulation Research Unit, Aeronautical Technology Directorate, Japan Aerospace Exploration AgencyA combustion simulation software tool, “HINOCA”, has been developed for automotive engine analysis. HINOCA is based on fully compressible Navier-Stokes equations, which are Reynolds-averaged (RANS) or spatially-filtered (LES), and employs the Cartesian grid and immersed boundary (IB) methods to reduce the mesh generation cost. In the present paper, focusing on flow simulations using k-ε models, a robust and reliable IB method coupled with wall functions is proposed. One major aspect of the method is that different IB cell information is employed for inviscid and viscous flux evaluations at fluid-IB cell interfaces. To improve the evaluation of wall shear stress, the shear stresses on the boundaries of an IB cell are transformed into a body force acting on the adjacent fluid cell. The computational method for ε-equation and the source terms of the k-equation near IB cells are modified so that the development of the turbulent boundary layer on a flat plate is well reproduced. The effects of these modifications are validated by the 2D Zero Pressure Gradient Flat Plate problem. To improve the mass conservation property of the IB method, multiple geometric parameters are defined for IB cells; that is, different image point information is immersed on IB cell centers for evaluating the inviscid flux on each cell interface. Evaluation with the Steady State Flow Bench problem shows that the proposed method drastically improves the mass conservation property of simulations and is able with a coarse mesh to reproduce flow structures obtained by LES with a much finer mesh.https://www.jstage.jst.go.jp/article/jfst/16/1/16_2021jfst0007/_pdf/-char/enimmersed boundary methodreynolds averaged navier-stokeswall functioninternal combustion enginecomplex geometry |
| spellingShingle | Hiroki YAO Taisuke NAMBU Yasuhiro MIZOBUCHI An immersed boundary method for practical simulations of high-Reynolds number flows by k-ε RANS models Journal of Fluid Science and Technology immersed boundary method reynolds averaged navier-stokes wall function internal combustion engine complex geometry |
| title | An immersed boundary method for practical simulations of high-Reynolds number flows by k-ε RANS models |
| title_full | An immersed boundary method for practical simulations of high-Reynolds number flows by k-ε RANS models |
| title_fullStr | An immersed boundary method for practical simulations of high-Reynolds number flows by k-ε RANS models |
| title_full_unstemmed | An immersed boundary method for practical simulations of high-Reynolds number flows by k-ε RANS models |
| title_short | An immersed boundary method for practical simulations of high-Reynolds number flows by k-ε RANS models |
| title_sort | immersed boundary method for practical simulations of high reynolds number flows by k ε rans models |
| topic | immersed boundary method reynolds averaged navier-stokes wall function internal combustion engine complex geometry |
| url | https://www.jstage.jst.go.jp/article/jfst/16/1/16_2021jfst0007/_pdf/-char/en |
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