Progress in DES for wall-modelled LES of complex internal flows

Mockett, Charles; Fuchs, Marian; Thiele, Frank

doi:10.1016/j.compfluid.2012.03.014

Cited by 47 publications

(27 citation statements)

References 24 publications

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“…11b) is used. The cell distribution is similar to the grid employed by Xiao and Jenny [18] (N xyz ≈ 0.1 • 10 6 ) and the constant-spaced grid by Mockett et al [7] (N xyz ≈ 1.5 • 10 6 ). The auxiliary RANS simulation in the dual-grid system is carried out on a wall-refined grid with the same topology in (x, y)-plane as the wall-refined LES grid, while the periodicity in spanwise direction is exploited to reduce the number of grid points.…”

Section: Periodic Hill Flowsupporting

confidence: 52%

“…Two computational grids are employed for the LES part of the dual-grid simulations, which enable a comparison with results of the Dual Mesh approach by Xiao and Jenny [18] and of the IDDES by Mockett et al [7]. First, standalone LES and hybrid simulations are run on a wall-refined grid with N x × N y × N z = 100 × 80 × 80 and maximum wall distance of the first grid points of y + 1 ≤ 1 on all walls (Fig.…”

Section: Periodic Hill Flowmentioning

confidence: 99%

“…The profile of the mean skin friction coefficient C f predicted by the hybrid model is compared to the benchmark and two reported IDDES results on a similar wall-refined and a y-constant-spaced grid [7] see Fig. 14.…”

Section: Periodic Hill Flowmentioning

confidence: 99%

“…One of the major hybrid schemes is the Detached Eddy Simulation (DES) family [4]. With multiple development stages, the more recent Improved Delayed DES (IDDES) model [5] is capable of predicting semi-confined flows with high accuracy on grids with low wall-parallel grid resolution, as demonstrated for example for periodic hill and backward-facing step flows [6,7].…”

Section: Introductionmentioning

confidence: 99%

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A Dual-Grid Hybrid RANS/LES Model for Under-Resolved Near-Wall Regions and its Application to Heated and Separating Flows

Nguyen

Uribe

Afgan

et al. 2019

Flow Turbulence Combust

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A hybrid RANS/LES model for high Reynolds number wall-bounded flows is presented, in which individual Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulations (LES) are computed in parallel on two fully overlapping grids. The instantaneous, fluctuating subgrid-scale stresses are blended with a statistical eddy viscosity model in regions where the LES grid is too coarse. In the present case, the hybrid model acts as a nearwall correction to the LES, while it retains the fluctuating nature of the flow field. The dual computation enables the LES to be run on isotropic grids with very low wall-normal and wall-parallel resolution, while the auxiliary RANS simulation is conducted on a wallrefined high-aspect ratio grid. Running distinct, progressively corrected simulations allows a clearer separation of the mean and instantaneous flow fields, compliant with the fundamentally dissimilar nature of RANS and LES. Even with the wall-nearest grid point lying far in the logarithmic layer, velocity and temperature predictions of a heated plane channel flow are corrected. For a periodic hill flow, the dual-grid system improves the boundary layer separation and velocity field prediction both for a constant-spaced and a wall-refined LES grid.

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Section: Periodic Hill Flowsupporting

confidence: 52%

Section: Periodic Hill Flowmentioning

confidence: 99%

Section: Periodic Hill Flowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Dual-Grid Hybrid RANS/LES Model for Under-Resolved Near-Wall Regions and its Application to Heated and Separating Flows

Nguyen

Uribe

Afgan

et al. 2019

Flow Turbulence Combust

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show abstract

“…Significant differences were exhibited in the results due to the use of two near-wall solution approaches using the y + 1 grid. An alternative hybrid RANS/LES strategy was used by Mockett, Fuchs, and Thiele (2012). The near-wall RANS modeling removed the Reynolds number scaling of the tangential grid spacing and the resolved turbulent fluctuations in the outer boundary layer were sustained by the LES.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of near-wall solution approaches for large-eddy simulations of flow in a centrifugal pump impeller

Yao

Yang²,

Wang

2016

Engineering Applications of Computational Fluid Mechanics

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The turbulent flow in a centrifugal pump impeller is bounded by complex surfaces, including blades, a hub and a shroud. The primary challenge of the flow simulation arises from the generation of a boundary layer between the surface of the impeller and the moving fluid. The principal objective is to evaluate the near-wall solution approaches that are typically used to deal with the flow in the boundary layer for the large-eddy simulation (LES) of a centrifugal pump impeller. Three nearwall solution approaches -the wall-function approach, the wall-resolved approach and the hybrid Reynolds averaged Navier-Stoke (RANS) and LES approach -are tested. The simulation results are compared with experimental results conducted through particle imaging velocimetry (PIV) and laser Doppler velocimetry (LDV). It is found that the wall-function approach is more sparing of computational resources, while the other two approaches have the important advantage of providing highly accurate boundary layer flow prediction. The hybrid RANS/LES approach is suitable for predicting steady-flow features, such as time-averaged velocities and hydraulic losses. Despite the fact that the wall-resolved approach is expensive in terms of computing resources, it exhibits a strong ability to capture a small-scale vortex and predict instantaneous velocity in the near-wall region in the impeller. The wall-resolved approach is thus recommended for the transient simulation of flows in centrifugal pump impellers. ARTICLE HISTORY

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Enhancement on parallel wall distance calculation methodology for partitioned unstructured grid

Zhi

Deng

Xiao

et al. 2022

Numerical Methods in Fluids

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Minimum distance to a solid wall is a primary parameter in turbulence models and overset grid assembly for computational fluid dynamics. In present work, a parallel advancing front method is proposed based on partitioned unstructured grids for the sake of further efficient wall distance computation. In order to overcome the inherent problem of conventional advancing front method in parallel environment, a novel "advancing twice and rippling once" strategy is developed to compute wall distance efficiently and further recover the accuracy. Significantly, the established framework is of modular nature to be easily extended to overset grid system for complex multi-body configurations. The performance of the developed techniques is evidenced by comparison with the existing alternative ways in terms of computing efficiency and accuracy. Subsequently, further case studies are performed to examine its capability to deal with complex engineering applications such as a full transportation, a wing-store configuration, a helicopter and a F-16 fighter with onboard payloads. Results show that the proposed advancing front methodology is in practice able to solve extremely complex geometries with both convex and concave shapes with high efficiency and robustness.

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Progress in DES for wall-modelled LES of complex internal flows

Cited by 47 publications

References 24 publications

A Dual-Grid Hybrid RANS/LES Model for Under-Resolved Near-Wall Regions and its Application to Heated and Separating Flows

A Dual-Grid Hybrid RANS/LES Model for Under-Resolved Near-Wall Regions and its Application to Heated and Separating Flows

Evaluation of near-wall solution approaches for large-eddy simulations of flow in a centrifugal pump impeller

Enhancement on parallel wall distance calculation methodology for partitioned unstructured grid

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