Simulation of Flow Around a Finite Rectangular Prism: Influence of Mesh, Model, and Subgrid Length Scale
This study investigates the flow field around a finite rectangular prism using both experimental and computational methods, with a particular focus on the influence of the turbulence approach adopted, the mesh resolution employed, and different subgrid length scales. Ten turbulence modelling and sim...
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2025-01-01
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| author | Xutong Zhang Maxime Savoie Mark K. Quinn Ben Parslew Alistair Revell |
| author_facet | Xutong Zhang Maxime Savoie Mark K. Quinn Ben Parslew Alistair Revell |
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| description | This study investigates the flow field around a finite rectangular prism using both experimental and computational methods, with a particular focus on the influence of the turbulence approach adopted, the mesh resolution employed, and different subgrid length scales. Ten turbulence modelling and simulation approaches, including both ‘scale-modelling’ Reynolds-Averaged Navier–Stokes (RANS) models and ‘scale-resolving’ Delayed Detached Eddy Simulation (DDES), were tested across six different mesh resolutions. A case with sharp corners allows the location of the flow separation to be fixed, which facilitates a focus on the separated flow region and, in this instance, the three-dimensional interaction of three such regions. The case, therefore, readily enables an assessment of the ‘grey-area’ issue, whereby some DDES methods demonstrate delayed activation of the scale-resolving model, impacting the size of flow recirculation. Experimental measurements were shown to agree well with reference data for the same geometry, after which particle image velocimetry (PIV) data were gathered to extend the reference dataset. Numerical predictions from the RANS models were generally quite reasonable but did not show improvement with further refinement, as one would expect, whereas DDES clearly demonstrated continuous improvement in predictive accuracy with progressive mesh refinement. The shear-layer-adapted (SLA) subgrid length scale (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mo>Δ</mo><mi>SLA</mi></msub></semantics></math></inline-formula>) displayed consistently superior performance compared to the more widely used length scale based on local cell volume, particularly for moderate mesh resolutions commonly employed in industrial settings with limited resources. In general, front-body separation and reattachment exhibited greater sensitivity to mesh refinement than wake resolution. Finally, in order to correlate the observed DDES mesh requirements with the observations from the converged RANS solutions, an approximation for the Taylor microscale was explored as a potential tool for mesh sizing. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-5b65c3197ad543658c531a4e16154cfd2025-01-24T13:31:52ZengMDPI AGEntropy1099-43002025-01-012716510.3390/e27010065Simulation of Flow Around a Finite Rectangular Prism: Influence of Mesh, Model, and Subgrid Length ScaleXutong Zhang0Maxime Savoie1Mark K. Quinn2Ben Parslew3Alistair Revell4Department of Mechanical and Aerospace Engineering, The University of Manchester, Manchester M1 3PL, UKDepartment of Mechanical and Aerospace Engineering, The University of Manchester, Manchester M1 3PL, UKDepartment of Mechanical and Aerospace Engineering, The University of Manchester, Manchester M1 3PL, UKDepartment of Mechanical and Aerospace Engineering, The University of Manchester, Manchester M1 3PL, UKDepartment of Mechanical and Aerospace Engineering, The University of Manchester, Manchester M1 3PL, UKThis study investigates the flow field around a finite rectangular prism using both experimental and computational methods, with a particular focus on the influence of the turbulence approach adopted, the mesh resolution employed, and different subgrid length scales. Ten turbulence modelling and simulation approaches, including both ‘scale-modelling’ Reynolds-Averaged Navier–Stokes (RANS) models and ‘scale-resolving’ Delayed Detached Eddy Simulation (DDES), were tested across six different mesh resolutions. A case with sharp corners allows the location of the flow separation to be fixed, which facilitates a focus on the separated flow region and, in this instance, the three-dimensional interaction of three such regions. The case, therefore, readily enables an assessment of the ‘grey-area’ issue, whereby some DDES methods demonstrate delayed activation of the scale-resolving model, impacting the size of flow recirculation. Experimental measurements were shown to agree well with reference data for the same geometry, after which particle image velocimetry (PIV) data were gathered to extend the reference dataset. Numerical predictions from the RANS models were generally quite reasonable but did not show improvement with further refinement, as one would expect, whereas DDES clearly demonstrated continuous improvement in predictive accuracy with progressive mesh refinement. The shear-layer-adapted (SLA) subgrid length scale (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mo>Δ</mo><mi>SLA</mi></msub></semantics></math></inline-formula>) displayed consistently superior performance compared to the more widely used length scale based on local cell volume, particularly for moderate mesh resolutions commonly employed in industrial settings with limited resources. In general, front-body separation and reattachment exhibited greater sensitivity to mesh refinement than wake resolution. Finally, in order to correlate the observed DDES mesh requirements with the observations from the converged RANS solutions, an approximation for the Taylor microscale was explored as a potential tool for mesh sizing.https://www.mdpi.com/1099-4300/27/1/65RANShybrid RANS LESDDESmesh refinementgrey areasubgrid length scale |
| spellingShingle | Xutong Zhang Maxime Savoie Mark K. Quinn Ben Parslew Alistair Revell Simulation of Flow Around a Finite Rectangular Prism: Influence of Mesh, Model, and Subgrid Length Scale Entropy RANS hybrid RANS LES DDES mesh refinement grey area subgrid length scale |
| title | Simulation of Flow Around a Finite Rectangular Prism: Influence of Mesh, Model, and Subgrid Length Scale |
| title_full | Simulation of Flow Around a Finite Rectangular Prism: Influence of Mesh, Model, and Subgrid Length Scale |
| title_fullStr | Simulation of Flow Around a Finite Rectangular Prism: Influence of Mesh, Model, and Subgrid Length Scale |
| title_full_unstemmed | Simulation of Flow Around a Finite Rectangular Prism: Influence of Mesh, Model, and Subgrid Length Scale |
| title_short | Simulation of Flow Around a Finite Rectangular Prism: Influence of Mesh, Model, and Subgrid Length Scale |
| title_sort | simulation of flow around a finite rectangular prism influence of mesh model and subgrid length scale |
| topic | RANS hybrid RANS LES DDES mesh refinement grey area subgrid length scale |
| url | https://www.mdpi.com/1099-4300/27/1/65 |
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