Towards Uncertainty Quantification of LES and URANS for the Buoyancy-Driven Mixing Process between Two Miscible Fluids—Differentially Heated Cavity of Aspect Ratio 4
Numerical simulations are subject to uncertainties due to the imprecise knowledge of physical properties, model parameters, as well as initial and boundary conditions. The assessment of these uncertainties is required for some applications. In the field of Computational Fluid Dynamics (CFD), the rel...
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| Format: | Article |
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MDPI AG
2021-04-01
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| Series: | Fluids |
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| Online Access: | https://www.mdpi.com/2311-5521/6/4/161 |
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| author | Philipp J. Wenig Ruiyun Ji Stephan Kelm Markus Klein |
| author_facet | Philipp J. Wenig Ruiyun Ji Stephan Kelm Markus Klein |
| author_sort | Philipp J. Wenig |
| collection | DOAJ |
| description | Numerical simulations are subject to uncertainties due to the imprecise knowledge of physical properties, model parameters, as well as initial and boundary conditions. The assessment of these uncertainties is required for some applications. In the field of Computational Fluid Dynamics (CFD), the reliable prediction of hydrogen distribution and pressure build-up in nuclear reactor containment after a severe reactor accident is a representative application where the assessment of these uncertainties is of essential importance. The inital and boundary conditions that significantly influence the present buoyancy-driven flow are subject to uncertainties. Therefore, the aim is to investigate the propagation of uncertainties in input parameters to the results variables. As a basis for the examination of a representative reactor test containment, the investigations are initially carried out using the Differentially Heated Cavity (DHC) of aspect ratio 4 with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>a</mi><mo>=</mo><mn>2</mn><mo>×</mo><msup><mn>10</mn><mn>9</mn></msup></mrow></semantics></math></inline-formula> as a test case from the literature. This allows for gradual method development for guidelines to quantify the uncertainty of natural convection flows in large-scale industrial applications. A dual approach is applied, in which Large Eddy Simulation (LES) is used as reference for the Unsteady Reynolds-Averaged Navier–Stokes (URANS) computations. A methodology for the uncertainty quantification in engineering applications with a preceding mesh convergence study and sensitivity analysis is presented. By taking the LES as a reference, the results indicate that URANS is able to predict the underlying mixing process at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>a</mi><mo>=</mo><mn>2</mn><mo>×</mo><msup><mn>10</mn><mn>9</mn></msup></mrow></semantics></math></inline-formula> and the variability of the result variables due to parameter uncertainties. |
| first_indexed | 2024-03-10T12:14:22Z |
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| id | doaj.art-5b138d86eea24df1aae35609ea0297e9 |
| institution | Directory Open Access Journal |
| issn | 2311-5521 |
| language | English |
| last_indexed | 2024-03-10T12:14:22Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Fluids |
| spelling | doaj.art-5b138d86eea24df1aae35609ea0297e92023-11-21T15:58:18ZengMDPI AGFluids2311-55212021-04-016416110.3390/fluids6040161Towards Uncertainty Quantification of LES and URANS for the Buoyancy-Driven Mixing Process between Two Miscible Fluids—Differentially Heated Cavity of Aspect Ratio 4Philipp J. Wenig0Ruiyun Ji1Stephan Kelm2Markus Klein3Institute of Applied Mathematics and Scientific Computing, Bundeswehr University Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, GermanyInstitute of Applied Mathematics and Scientific Computing, Bundeswehr University Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, GermanyInstitute for Energy and Climate Research (IEK-6), Forschungszentrum Jülich GmbH, 52425 Jülich, GermanyInstitute of Applied Mathematics and Scientific Computing, Bundeswehr University Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, GermanyNumerical simulations are subject to uncertainties due to the imprecise knowledge of physical properties, model parameters, as well as initial and boundary conditions. The assessment of these uncertainties is required for some applications. In the field of Computational Fluid Dynamics (CFD), the reliable prediction of hydrogen distribution and pressure build-up in nuclear reactor containment after a severe reactor accident is a representative application where the assessment of these uncertainties is of essential importance. The inital and boundary conditions that significantly influence the present buoyancy-driven flow are subject to uncertainties. Therefore, the aim is to investigate the propagation of uncertainties in input parameters to the results variables. As a basis for the examination of a representative reactor test containment, the investigations are initially carried out using the Differentially Heated Cavity (DHC) of aspect ratio 4 with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>a</mi><mo>=</mo><mn>2</mn><mo>×</mo><msup><mn>10</mn><mn>9</mn></msup></mrow></semantics></math></inline-formula> as a test case from the literature. This allows for gradual method development for guidelines to quantify the uncertainty of natural convection flows in large-scale industrial applications. A dual approach is applied, in which Large Eddy Simulation (LES) is used as reference for the Unsteady Reynolds-Averaged Navier–Stokes (URANS) computations. A methodology for the uncertainty quantification in engineering applications with a preceding mesh convergence study and sensitivity analysis is presented. By taking the LES as a reference, the results indicate that URANS is able to predict the underlying mixing process at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>R</mi><mi>a</mi><mo>=</mo><mn>2</mn><mo>×</mo><msup><mn>10</mn><mn>9</mn></msup></mrow></semantics></math></inline-formula> and the variability of the result variables due to parameter uncertainties.https://www.mdpi.com/2311-5521/6/4/161uncertainty quantificationsensitivity analysisnatural convectionmixing processdifferentially heated cavityLES |
| spellingShingle | Philipp J. Wenig Ruiyun Ji Stephan Kelm Markus Klein Towards Uncertainty Quantification of LES and URANS for the Buoyancy-Driven Mixing Process between Two Miscible Fluids—Differentially Heated Cavity of Aspect Ratio 4 Fluids uncertainty quantification sensitivity analysis natural convection mixing process differentially heated cavity LES |
| title | Towards Uncertainty Quantification of LES and URANS for the Buoyancy-Driven Mixing Process between Two Miscible Fluids—Differentially Heated Cavity of Aspect Ratio 4 |
| title_full | Towards Uncertainty Quantification of LES and URANS for the Buoyancy-Driven Mixing Process between Two Miscible Fluids—Differentially Heated Cavity of Aspect Ratio 4 |
| title_fullStr | Towards Uncertainty Quantification of LES and URANS for the Buoyancy-Driven Mixing Process between Two Miscible Fluids—Differentially Heated Cavity of Aspect Ratio 4 |
| title_full_unstemmed | Towards Uncertainty Quantification of LES and URANS for the Buoyancy-Driven Mixing Process between Two Miscible Fluids—Differentially Heated Cavity of Aspect Ratio 4 |
| title_short | Towards Uncertainty Quantification of LES and URANS for the Buoyancy-Driven Mixing Process between Two Miscible Fluids—Differentially Heated Cavity of Aspect Ratio 4 |
| title_sort | towards uncertainty quantification of les and urans for the buoyancy driven mixing process between two miscible fluids differentially heated cavity of aspect ratio 4 |
| topic | uncertainty quantification sensitivity analysis natural convection mixing process differentially heated cavity LES |
| url | https://www.mdpi.com/2311-5521/6/4/161 |
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