Anisotropy analysis of turbulent swirl flow

Radenkovic, R Darko; Burazer, Jela M.; Novkovic, M Djordje

doi:10.5937/fmet1401019r

Cited by 24 publications

(8 citation statements)

References 8 publications

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“…8(a) and 8(b) show contours of the second invariant of the anisotropy tensor II a ¼ a ij a ji as predicted by RANS and LES. This invariant is a useful indicator of the degree of stress anisotropy: it ranges in value from 0 (indicating isotropic turbulence) up to 2/3 (indicating a high degree of anisotropy) [26,27]. As Fig.…”

Section: Rans Setupmentioning

confidence: 99%

Uncertainty Analysis and Data-Driven Model Advances for a Jet-in-Crossflow

Ling

Ruiz

Lacaze

et al. 2016

Journal of Turbomachinery

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For film cooling of combustor linings and turbine blades, it is critical to be able to accurately model jets-in-crossflow. Current Reynolds-averaged Navier–Stokes (RANS) models often give unsatisfactory predictions in these flows, due in large part to model form error, which cannot be resolved through calibration or tuning of model coefficients. The Boussinesq hypothesis, upon which most two-equation RANS models rely, posits the existence of a non-negative scalar eddy viscosity, which gives a linear relation between the Reynolds stresses and the mean strain rate. This model is rigorously analyzed in the context of a jet-in-crossflow using the high-fidelity large eddy simulation data of Ruiz et al. (2015, “Flow Topologies and Turbulence Scales in a Jet-in-Cross-Flow,” Phys. Fluids, 27(4), p. 045101), as well as RANS k–ϵ results for the same flow. It is shown that the RANS models fail to accurately represent the Reynolds stress anisotropy in the injection hole, along the wall, and on the lee side of the jet. Machine learning methods are developed to provide improved predictions of the Reynolds stress anisotropy in this flow.

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Section: Rans Setupmentioning

confidence: 99%

Uncertainty Analysis and Data-Driven Model Advances for a Jet-in-Crossflow

Ling

Ruiz

Lacaze

et al. 2016

Journal of Turbomachinery

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“…The anisotropy of Reynolds stresses has significant influence on the accuracy of first-order closure models. Radenkovic et al [10] analysed main types of Reynolds stresses anisotropy in case of swirl flow in a straight pipe. They performed analyses of the Reynolds stresses using invariant theory.…”

Section: Introductionmentioning

confidence: 99%

On the influence of turbulent kinetic energy level on accuracy of k − ε and LRR turbulence models

Novkovic

Burazer²,

Ćoćić³

et al. 2018

Theor appl mech (Belgr)

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This paper presents research regarding the influence of turbulent kinetic energy (TKE) level on accuracy of Reynolds averaged Navier-Stokes (RANS) based turbulence models. A theoretical analysis of influence TKE level on accuracy of the RANS turbulence models has been performed according to the Boussinesq hypothesis definition. After that, this theoretical analysis has been investigated by comparison of numerically and experimentally obtained results on the test case of a steady-state incompressible swirl-free flow in a straight conical diffuser named Azad diffuser. Numerical calculations have been performed using the OpenFOAM CFD software and first and secondorder closure turbulence models. TKE level, velocity profiles and Reynolds stresses have been calculated downstream in four different cross sections of the diffuser. Certain conclusions about modeling turbulent flows by − and LRR turbulence models have been made by comparing the velocity profiles, TKE distribution and Reynolds stresses on the selected cross sections.2010 Mathematics Subject Classification: 76F10.

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“…However, this turbulence model is fairly ineffective in simulating anisotropic turbulence due to the theoretical deficiency for anisotropic nature of turbulent motions, although it is widely applied in engineering. Thus, numerous studies have been carried out to further understand the physical aspects of anisotropic turbulent flows and vortex dynamics [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Characteristics of Turbulence Dissipation in Swirling Flow: A Direct Numerical Simulation Study

Yang

Gui

Xie

et al. 2015

Advances in Mathematical Physics

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This study investigates the anisotropic characteristics of turbulent energy dissipation rate in a rotating jet flow via direct numerical simulation. The turbulent energy dissipation tensor, including its eigenvalues in the swirling flows with different rotating velocities, is analyzed to investigate the anisotropic characteristics of turbulence and dissipation. In addition, the probability density function of the eigenvalues of turbulence dissipation tensor is presented. The isotropic subrange of PDF always exists in swirling flows relevant to small-scale vortex structure. Thus, with remarkable large-scale vortex breakdown, the isotropic subrange of PDF is reduced in strongly swirling flows, and anisotropic energy dissipation is proven to exist in the core region of the vortex breakdown. More specifically, strong anisotropic turbulence dissipation occurs concentratively in the vortex breakdown region, whereas nearly isotropic turbulence dissipation occurs dispersively in the peripheral region of the strong swirling flows.

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Anisotropy analysis of turbulent swirl flow

Abstract: Anisotropy invariant map proposed by Lumley and

Cited by 24 publications

References 8 publications

Uncertainty Analysis and Data-Driven Model Advances for a Jet-in-Crossflow

Uncertainty Analysis and Data-Driven Model Advances for a Jet-in-Crossflow

On the influence of turbulent kinetic energy level on accuracy of k − ε and LRR turbulence models

Anisotropic Characteristics of Turbulence Dissipation in Swirling Flow: A Direct Numerical Simulation Study

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