A new non-linear RANS model with enhanced near-wall treatment of turbulence anisotropy

Research output: Contribution to journalArticle

Abstract

A new ω-based non-linear eddy-viscosity model is proposed. It was developed based on the original k -ω model and formulated using a quadratic stress-strain relation for the Reynolds stress tensor, with an added realisability condition. For enhanced treatment of nearwall turbulence anisotropy, a formulation that scales only with the turbulent Reynolds number is proposed for the first time. The new model has been implemented in the open-source Computational Fluid Dynamics (CFD) package OpenFOAM and validated against plane channel flow, a zero-pressure-gradient flat plate, and a U-bend curved channel configuration. To
further assess the performance of the model for more complex geometries, it has been tested on configurations relevant to automotive applications. Overall, the new model outperforms the standard k - ω model. For example, on a curved channel, improved predictions for the minimum pressure and maximum skin friction of approximately 50% are obtained. Improved predictions are also obtained for quantities of practical engineering relevance, such as the pressure distribution along the wall of a sudden expansion diffuser, a configuration used to inform the design of automotive exhaust systems. This demonstrates that the proposed model has important practical applications for internal flows where anisotropic turbulence effects dominate.
Original languageEnglish
Pages (from-to)293-313
Number of pages21
JournalApplied Mathematical Modelling
Volume82
Early online date28 Jan 2020
DOIs
Publication statusE-pub ahead of print - 28 Jan 2020

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Nonlinear Model
Anisotropy
Turbulence
Configuration
Model
Internal Flow
Eddy Viscosity
Diffuser
Reynolds Stress
Skin Friction
Channel Flow
Skin friction
Prediction
Flat Plate
Stress Tensor
Complex Geometry
Pressure Distribution
Pressure Gradient
Channel flow
Pressure gradient

Keywords

  • Turbulence
  • OpenFOAM
  • Anisotropy
  • Swirling flow
  • Catalyst
  • Modelling
  • CFD

ASJC Scopus subject areas

  • Automotive Engineering
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes
  • Modelling and Simulation

Cite this

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title = "A new non-linear RANS model with enhanced near-wall treatment of turbulence anisotropy",
abstract = "A new ω-based non-linear eddy-viscosity model is proposed. It was developed based on the original k -ω model and formulated using a quadratic stress-strain relation for the Reynolds stress tensor, with an added realisability condition. For enhanced treatment of nearwall turbulence anisotropy, a formulation that scales only with the turbulent Reynolds number is proposed for the first time. The new model has been implemented in the open-source Computational Fluid Dynamics (CFD) package OpenFOAM and validated against plane channel flow, a zero-pressure-gradient flat plate, and a U-bend curved channel configuration. Tofurther assess the performance of the model for more complex geometries, it has been tested on configurations relevant to automotive applications. Overall, the new model outperforms the standard k - ω model. For example, on a curved channel, improved predictions for the minimum pressure and maximum skin friction of approximately 50{\%} are obtained. Improved predictions are also obtained for quantities of practical engineering relevance, such as the pressure distribution along the wall of a sudden expansion diffuser, a configuration used to inform the design of automotive exhaust systems. This demonstrates that the proposed model has important practical applications for internal flows where anisotropic turbulence effects dominate.",
keywords = "Turbulence, OpenFOAM, Anisotropy, Swirling flow, Catalyst, Modelling, CFD",
author = "Fadhila, {Hasna Nur} and Humberto Medina and Svetlana Aleksandrova and Stephen Benjamin",
year = "2020",
month = "1",
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language = "English",
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