Improvements in Zonal Detached Eddy Simulation for Wall Modeled Large Eddy Simulation

Renard, Nicolas; Deck, Sébastien

doi:10.2514/1.j054143

Cited by 26 publications

(32 citation statements)

References 34 publications

(56 reference statements)

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“…For WMLES, the RANS/LES interface height should not depend on the mesh resolution ( [8]) and scale in outer units (i.e. be at a constant y/δ [6] or at the geometric centre of the logarithmic layer [25], [26]). The interface may typically be positioned from a pre-processing of the RANS flow field used as the initial condition for the ZDES simulation.…”

Section: A Wmles Strategy: Mode III Of Zdesmentioning

confidence: 99%

“…3). Assessing the resolved fraction of turbulent mean skin friction by means of the FIK identity [11] [7] [6] shows that more than 90 % of the turbulent contribution is resolved at Re θ = 13 000 with the log layer interface setting [26], a figure that increases with the Reynolds number. With the lower interface setting y + interface = 3.9 √ Re τ however, streamwise oscillations of mean skin friction are visible ( fig.…”

Section: Accuracy Resolution and Streamwise Evolution Of Skin Frictionmentioning

confidence: 99%

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On the Convection Velocity of Wall-Bounded Turbulence Resolved by ZDES Mode III at $$Re_\theta = 13 000$$ R e θ = 13000

Renard

Deck

2018

Progress in Hybrid RANS-LES Modelling

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WMLES simulations of a flat-plate zero-pressure-gradient boundary layer are done with the Zonal Detached Eddy Simulation Mode III technique over a wide range of Reynolds numbers 3 150 ≤ Re θ ≤ 14 000. A WMLES field is compared with the WRLES interpolated onto the WMLES mesh. Two interface heights are considered, y interface = 0.1δ and y + interface = 3.9 √ Re τ. The prediction and resolved fraction of mean skin friction is discussed, as well as remaining issues, especially in the logarithmic layer. An excess of high-wavelength streamwise velocity fluctuations is observed below the RANS/LES interface with y + interface = 3.9 √ Re τ , and studied by a spectral convection velocity analysis, leading to the suggestion that it may be a footprint of coherent structures located further away from the wall.

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Section: A Wmles Strategy: Mode III Of Zdesmentioning

confidence: 99%

Section: Accuracy Resolution and Streamwise Evolution Of Skin Frictionmentioning

confidence: 99%

On the Convection Velocity of Wall-Bounded Turbulence Resolved by ZDES Mode III at $$Re_\theta = 13 000$$ R e θ = 13000

Renard

Deck

2018

Progress in Hybrid RANS-LES Modelling

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“…A recent extension to ZDES, introduced by Deck et al 35,41,42 and improved by Renard et al, 43 in which the model acts in a wall-modeled LES (WMLES) mode has also been added to LAVA. Here RANS is used in the inner layer of the attached boundary layer up to a user selected wall distance (typically 10% of local BL thickness 43 ), and interfaces to an outer LES (no forcing or filtering is applied).…”

Section: Iiia3 Zonal Hybrid Rans/les Modelmentioning

confidence: 99%

“…In this section we will study the effects of the interface location h w between RANS (which serves as a wallmodel in ZDES Mode 3) and the outer LES simulation. According to Deck 42 and Renard and Deck 43 it is c Q-criterion: second invariant of the velocity-gradient tensor.…”

Section: Ivb1 Zdes Mode 3 -Influence Of Interface Locationmentioning

confidence: 99%

Application of Lattice Boltzmann and Navier-Stokes Methods to NASA’s Wall Mounted Hump

Kiris

Stich

Housman

et al. 2018

2018 Fluid Dynamics Conference

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Lattice Boltzmann (LB) based Large Eddy Simulation (LES), Reynolds-averaged Navier-Stokes (RANS) as well as hybrid RANS/LES methods within the Launch Ascent and Vehicle Aerodynamics (LAVA) solver framework are applied to NASA's wall-mounted hump. Computational results are compared with experiments performed by Greenblatt et al. 1 A detailed comparison between the accuracy and resolution requirements of the two approaches for turbulence resolving simulations, as well as the suitability of different grid paradigms (body-fitted curvilinear and block structured Cartesian) are presented. This test case is part of NASA's Revolutionary Computational Aerosciences (RCA) sub-project which addresses the technical challenge of predicting flow separation and reattachment accurately. Improvements in predictive accuracy by as much as 90% are demonstrated using LB as well as hybrid RANS/LES approaches compared to state-of-the-art steady state

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“…Renard and Deck [10] used zonal DES (ZDES) [11] for WMLES of a zero-pressure-gradient turbulent boundary layer with an improved positioning for the RANS-LES interface by placing the transition in the geometric center of the logarithmic layer. Good agreement was achieved with skin friction correlations.…”

Section: Introductionmentioning

confidence: 99%

The Role of Forcing and Eddy Viscosity Variation on the Log-Layer Mismatch Observed in Wall-Modeled Large-Eddy Simulations

DeLeon

Şenocak

2018

Journal of Fluids Engineering

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We investigate the role of the bulk eddy-viscosity variation on the well-known log-layer mismatchproblem. An analysis of the mean momentum-balance shows that the modeled stress term close to the wall can dominate because of the bulk eddy-viscosity. Consequently, the momentum-balance equation lacks a degree-of-freedom and the mean velocity conforms to an incorrect profile to satisfy the momentum-balance. We show that zonal enforcement of the target mass flow-rate can be an effective strategy to introduce an additional degree of freedom to the mean momentumbalance, which led to a significant reduction in the log-layer mismatch. When the mass flow-rate is enforced zonally, the filtered velocity field attains its own constant velocity-scale above the Reynolds-averaged field, supporting the hypothesis that there exists an artificial boundary layer above the Reynolds-averaged region. We simulate turbulent channel flows at friction Reynolds numbers of 2000 and 5200 on coarse meshes that would put the first point away from the wall well into the logarithmic layer. Second-order turbulence statistics and one-dimensional velocity spectra agree well with the direct numerical simulation benchmark data when results are normalized by the velocity-scale extracted from the filtered velocity field. Additionally, the error in the skin-friction coefficient for friction Reynolds numbers of 2000 decreased from 14.1% to 2.5% when we enforced the mass flow-rate zonally.

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Improvements in Zonal Detached Eddy Simulation for Wall Modeled Large Eddy Simulation

Cited by 26 publications

References 34 publications

On the Convection Velocity of Wall-Bounded Turbulence Resolved by ZDES Mode III at $$Re_\theta = 13 000$$ R e θ = 13000

On the Convection Velocity of Wall-Bounded Turbulence Resolved by ZDES Mode III at $$Re_\theta = 13 000$$ R e θ = 13000

Application of Lattice Boltzmann and Navier-Stokes Methods to NASA’s Wall Mounted Hump

The Role of Forcing and Eddy Viscosity Variation on the Log-Layer Mismatch Observed in Wall-Modeled Large-Eddy Simulations

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