Budget Analysis of Turbulent Kinetic Energy in Corner Separation : Rans vs Les

Monier, Jean-François; Gao, Feng; Boudet, Jérôme; Shao, Lei; Lu, Lipeng

doi:10.7712/100016.2313.7719

Cited by 3 publications

(2 citation statements)

References 22 publications

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“…This is largely because of its cost-effectiveness, numerical robustness, and relatively easy of use. However, several eddy viscosity based RANS closure models that are commonly used in industry, such as Spalart-Allmaras (SA) model (Spalart and Allmaras, 1992) and Menter's hybrid k-ω k-ε ⁄ model (Menter, 1994(Menter, , 2003, were found to over-predict the extent of corner separation (Liu et al, 2012;Monier et al, 2016). One of the sources of modelling uncertainties occurs in the Boussinesq constitutive relation, which was introduced for the Reynolds-stress closure in the mean transport equations.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Corner Separation Prediction Using an Explicit Nonlinear RANS Closure

Sun¹,

Xu²

2020

Proceedings of Global Power &Amp; Propulsion Society

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In this paper, an investigation into the effect of explicit non-linear turbulence modelling on anisotropic turbulence flows is presented. Such anisotropic turbulence flows are typified in the corner separations in turbomachinery. The commonly used Reynolds-Averaged Navier-Stokes (RANS) turbulence closures, in which the Reynolds stress tensor is modelled by the Boussinesq (linear) constitutive relation with the mean strain-rate tensor, often struggle to predict corner separation with reasonable accuracy. The physical reason for this modelling deficiency is partially attributable to the Boussinesq hypothesis which does not count for the turbulence anisotropy, whilst in a corner separation, the flow is subject to three-dimensional (3D) shear and the effects due to turbulence anisotropy may not be ignored. In light of this, an explicit non-linear Reynolds stress-strain constitutive relation developed by Menter et al. is adopted as a modification of the Reynolds-stress anisotropy. Coupled with the Menter's hybrid k-ω k-ε ⁄ turbulence model, this nonlinear constitutive relation gives significantly improved predictions for the corner separation flows within a compressor cascade, at both the design and off-design flow conditions. The mean flow field are studied to further investigate the physical reasons for these improvements, highlighting its potential for the widespread applications in the corner separation prediction.

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Section: Introductionmentioning

confidence: 99%

Improvement of Corner Separation Prediction Using an Explicit Nonlinear RANS Closure

Sun¹,

Xu²

2020

Proceedings of Global Power &Amp; Propulsion Society

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show abstract

“…The first simulation uses the classical Boussinesq constitutive relation, while the second simulation uses the quadratic constitutive relation (QCR) (Spalart, 2000). This method of analysis was previously applied on a corner separation in a linear cascade (Monier et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Budget Analysis of Turbulent Kinetic Energy in a Tip-Leakage Flow of a Single Blade: RANS Vs Zonal LES

Monier

Boudet

Caro

et al. 2017

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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This study aims at analyzing the modeling of turbulence in a tip-leakage flow. The academic configuration considered is made of a single airfoil and a flat casing, with clearance, at Re=9.3e5. For characterising the turbulence, a zonal large-eddy simulation (ZLES), validated against experimental data, is considered as reference. ZLES was previously shown to describe precisely the flow features in the tip region, including the Reynolds stresses. Two steady Reynolds-averaged Navier-Stokes (RANS) simulations, using Wilcox's k-ω model, are evaluated against this reference. The first simulation uses the Boussinesq constitutive relation, whereas the second simulation relies on the quadratic constitutive relation (QCR). The analysis focuses on the mean velocities, the Reynolds stresses and a term-to-term decomposition of the turbulent kinetic energy budget. RANS is shown to underestimate the vorticity of the flow, the Reynolds stresses and the turbulent kinetic energy budget terms. The QCR has little effects on these deficits. KEYWORDS TIP-LEAKAGE FLOW, SINGLE AIRFOIL, RANS, LES, REYNOLDS STRESSES, TURBULENT KINETIC ENERGY BUDGET NOMENCLATURE M Mach number ∆x + , ∆y + , ∆z + Cell sizes at the wall, in wall O Normalized rotation tensor units Re c Reynolds number based on Π Sub-grid scale stress tensor the chord length of the blade Ξ Numerical residual tensor U Free-stream velocity δ ij Kroeneker symbol c Chord-length of the blade ρ Density h Tip-clearance height τ Viscous stress tensor k Turbulent kinetic energy τ t \τ QCR t Reynolds stress tensor with p Pressure Boussinesq constitutive u 1 , u 2 , u 3 Stream-wise (resp. transverse relation \with QCR and span-wise) velocities ω Turbulent kinetic energy x 1 , x 2 , x 3 Stream-wise (resp. transverse specific dissipation rate and span-wise) directions

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Reduction in endwall flow losses in turbine blade with the use of sweep in leading edge of the blade

Mourya

Subbarao

2023

J Braz. Soc. Mech. Sci. Eng.

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Budget Analysis of Turbulent Kinetic Energy in Corner Separation : Rans vs Les

Cited by 3 publications

References 22 publications

Improvement of Corner Separation Prediction Using an Explicit Nonlinear RANS Closure

Improvement of Corner Separation Prediction Using an Explicit Nonlinear RANS Closure

Budget Analysis of Turbulent Kinetic Energy in a Tip-Leakage Flow of a Single Blade: RANS Vs Zonal LES

Reduction in endwall flow losses in turbine blade with the use of sweep in leading edge of the blade

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