An investigation of LES and Hybrid LES/RANS models for predicting 3-D diffuser flow

Abe, Ken; Ohtsuka, Tadashi

doi:10.1016/j.ijheatfluidflow.2010.03.005

Cited by 16 publications

(12 citation statements)

References 20 publications

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“…where C s is calculated by the dynamic procedure of Equation (11). It should be noted that C s in the ODM model does not require any averaging over homogeneous direction or ad hoc clipping technique to avoid negative Smagorinsky constants.…”

Section: One-equation Dynamic Model (Odm)mentioning

confidence: 99%

“…Schneider et al [10] performed the LES and RANS calculations for two asymmetrical three-dimensional diffusers and validated LES with wall function delivering the results within the accuracy of experimental data. Abe and Ohtsuka [11] investigated high Reynolds-number complex turbulent flows in a 3D diffuser using LES and hybrid LES/RANS models. Kaltenbach et al [6] elaborately studied the flow in a planar asymmetric diffuser using LES with the dynamic Smagorinsky model.…”

Section: Introductionmentioning

confidence: 99%

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Large-Eddy Simulation of an Asymmetric Plane Diffuser: Comparison of Different Subgrid Scale Models

Tang

Lei

et al. 2019

Symmetry

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Large-eddy simulation (LES) of separated turbulent flow through an asymmetric plane diffuser is investigated. The outcome of an actual LES depends on the quality of the subgrid-scale (SGS) model, as well as the accuracy of the numerical method used to solve the equations for the resolved scales. In this paper, we focus on the influence of SGS models for LES of the diffuser flow through using a high-order finite difference method to solve the equations for the resolved scales. Six resolutions are computed to investigate the influence of mesh resolution. Four existing SGS models, a new one-equation dynamic SGS model and a direct numerical simulation (DNS) are conducted in the diffuser flow. A series of computational analyses is performed to assess the performance of different SGS models on the coarse grids. By comparison with the experiment and DNS, the results produced by the new one-equation dynamic model give better agreement with experiment and DNS than the four other existing SGS models.

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Section: One-equation Dynamic Model (Odm)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulation of an Asymmetric Plane Diffuser: Comparison of Different Subgrid Scale Models

Tang

Lei

et al. 2019

Symmetry

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“…The RANS simulations failed in predicting accurately the location and size of the reverse flow region while the LES results on a fine grid were in good agreement with experimental data. Other studies including Abe and Ohtsuka (2010) and Jakirlić et al (2010) compared the accuracy of hybrid LES/RANS (HLR) models with pure LES in terms of the mean flow separation within the first diffuser D1. These papers revealed that HLR is able to deliver similar results to LES at reduced computational cost as HLR simulations were run on coarser meshes.…”

Section: Introductionmentioning

confidence: 99%

Flow Separation Dynamics in Three-Dimensional Asymmetric Diffusers

Hajaali

Stoesser

2021

Flow Turbulence Combust

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The mean and instantaneous flow separation of two different three-dimensional asymmetric diffusers is analysed using the data of large-eddy simulations. The geometry of both diffusers under investigation is based on the experimental configuration of Cherry et al. (Int J Heat Fluid Flow 29(3):803–811, 2008). The two diffusers feature similar area ratios of $$\mathrm{AR}=4.8$$ AR = 4.8 and $$\mathrm{AR}=4.5$$ AR = 4.5 while exhibiting differing asymmetric expansion ratios of $$\mathrm{AER}=4.5$$ AER = 4.5 or $$\mathrm{AER}=2.0$$ AER = 2.0 , respectively. The Reynolds number based on the averaged inlet velocity and height of the inlet duct is approximately $${\textit{Re}}=10{,}000$$ Re = 10 , 000 . The time-averaged flow in both diffusers in terms of streamwise velocity profiles or the size and location of the mean backflow region are validated using experimental data. In general good agreement of simulated results with the experimental data is found. Further quantification of the flow separation behaviour and unsteadiness using the backflow coefficient reveals the volume portion in which the instantaneous reversal flow evolves. This new approach investigates the cumulative fractional volume occupied by the instantaneous backflow throughout the simulation, a power density spectra analysis of their time series reveals the periodicity of the growth and reduction phases of the flow separation within the diffusers. The dominating turbulent events responsible for the formation of the energy-containing motions including ejection and sweep are examined using the quadrant analysis at various locations. Finally, isourfaces of the Q-criterion visualise the instantaneous flow and the origin and fate of coherent structures in both diffusers.

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“…They found that the pressure-strain models were performing poor in the near wall region. Abe and Ohtsuka (2010) presented the analysis of all the terms in the Reynolds stress equation and turbulent kinetic energy equation in turbulent channel flow. They observed that, in an axial normal stress equation, the production almost balances with some of the dissipation and the velocity pressure gradient correlation.…”

Section: Introductionmentioning

confidence: 99%

Comparison of k–ε, RSM and LES models for the prediction of flow pattern in jet loop reactor

Khan

Joshi

2015

Chemical Engineering Science

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An investigation of LES and Hybrid LES/RANS models for predicting 3-D diffuser flow

Cited by 16 publications

References 20 publications

Large-Eddy Simulation of an Asymmetric Plane Diffuser: Comparison of Different Subgrid Scale Models

Large-Eddy Simulation of an Asymmetric Plane Diffuser: Comparison of Different Subgrid Scale Models

Flow Separation Dynamics in Three-Dimensional Asymmetric Diffusers

Comparison of k–ε, RSM and LES models for the prediction of flow pattern in jet loop reactor

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