Near-Wall Modeling of Turbulent Flow and Heat Transfer Using a Spectral Element CFD Solver

Pal, Pinaki; Ameen, Mohammed; Xu, Chao

doi:10.2514/6.2022-1369

Cited by 3 publications

(1 citation statement)

References 10 publications

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“…As the reader will notice from the results of this paper, the modelled region is highly sensitive to the discretization method, emphasizing the need for the present analysis. In parallel to the present paper, a similar implementation to wmLES has been performed by Argone National Laboratory with successful results in Pal et al (2022). The authors include a thermal law-of-the wall, complementing well the present paper.…”

Section: Introductionmentioning

confidence: 90%

Implementation and Validation of an Algebraic Wall Model for LES in Nek5000

Gillyns

Buckingham

Winckelmans

2022

Flow Turbulence Combust

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Turbulent flows are most often wall-bounded, rendering the treatment of the wall essential. In this work, the near-wall layer is modelled in large eddy simulations which enables simulating high Reynolds number flows. An algebraic wall model has been implemented in the spectral element code Nek5000. It consists of an approximate boundary condition that relates the wall shear stress to the velocity measured close to the wall, on the upper edge of the first spectral element. The wall shear stress model approximates the law of the wall for hydraulically smooth cases. The model is applied to channel flow cases at $$Re_{\tau }=1000$$ R e τ = 1000 and at $$Re_{\tau }=5200$$ R e τ = 5200 . The wmLES results obtained with the present implementation are seen to compare very well with those of reference direct numerical simulations in the resolved region. They also remain remarkably close to the reference results for a large part of the under-resolved region; which is not necessarily the case when using low order implementations and even other types of high order discretizations, as found in the literature. Various parameters are studied such as the time averaging, the height of the near wall under-resolved element, and the mesh requirements. The obtained results indicate that accurate results can be obtained with Nek5000 at a reduced cost thanks to this newly implemented wmLES model. This work provides the necessary guidelines for simple flows, and it will serve as a first basis for simulating more complex flows at high Reynolds numbers.

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Section: Introductionmentioning

confidence: 90%

Implementation and Validation of an Algebraic Wall Model for LES in Nek5000

Gillyns

Buckingham

Winckelmans

2022

Flow Turbulence Combust

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Boundary Conditions for Wall-Modelled Large-Eddy Simulation Using Spectral Element Discretization

Mukha,

Brethouwer,

Schlatter

2023

ERCOFTAC Series

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Applications of wall-models to implicit large eddy simulations in the spectral/hp element method

Huang

Wang

Wu³

et al. 2022

Physics of Fluids

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An implicit large eddy simulation (iLES) method based on a spectral vanishing viscosity (SVV) method has been well established in the framework of the spectral/ hp element method (which is called the SVV-iLES method), and the SVV regularization introduces proper dissipation to the numerical scheme, which in turn reduces the truncation error and the uncertainty in computation. However, SVV-iLES is still limited to moderate Reynolds numbers due to the huge computational cost in resolving the inner part of the boundary layer. By modeling the near-wall layer, a wall-model coupling strategy, tailored to the features of the SVV-iLES, is proposed to substantially reduce the computational cost. This work is the first to construct the wall model of SVV-iLES based on the spectral/ hp element method, and the practice rules can be regarded as guidelines for the application of the wall model to iLES with high order schemes. Numerical investigations for a well-established benchmark problem of the turbulent channel flow are implemented by the proposed wall-modeled SVV-iLES. The results obtained are consistent with the reference direct numerical simulation (DNS) data at different Reynolds numbers considered. The effect of the time-averaged velocity at the matching interface is examined, and the results suggest that the instantaneous velocity can be directly used in the algebraic wall-model, which in turn could speed up the computation. Additionally, a comparison between the classical log-law and Reichardt's law models reveals that there are no significant differences in statistical quantities in the logarithmic region. Finally, it was found that, at similar grid resolution, the p-type refinement shows better agreement with the reference DNS results.

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Near-Wall Modeling of Turbulent Flow and Heat Transfer Using a Spectral Element CFD Solver

Cited by 3 publications

References 10 publications

Implementation and Validation of an Algebraic Wall Model for LES in Nek5000

Implementation and Validation of an Algebraic Wall Model for LES in Nek5000

Boundary Conditions for Wall-Modelled Large-Eddy Simulation Using Spectral Element Discretization

Applications of wall-models to implicit large eddy simulations in the spectral/hp element method

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