Behaviour of turbulence models near a turbulent/non-turbulent interface revisited

Ferrey, Paul; Aupoix, B.

doi:10.1016/j.ijheatfluidflow.2006.03.022

Cited by 6 publications

(1 citation statement)

References 10 publications

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“…The turbulent boundary-layer edge region should ideally yield low µ t values such that the proper analytic behavior of the turbulence model is preserved [32,74] and robustness of the boundary-layer is guaranteed with respect to low external disturbances [31]. Indeed, in the µ t /µ fields of Fig.…”

Section: And (2)mentioning

confidence: 99%

Prediction of Separation-Induced Transition on the SD7003 Airfoil Using Algebraic Transition Triggering

et al. 2019

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Section: And (2)mentioning

confidence: 99%

Prediction of Separation-Induced Transition on the SD7003 Airfoil Using Algebraic Transition Triggering

et al. 2019

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Effects of mean shear on the local turbulent entrainment process

et al. 2013

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We report on effects of mean shear on the turbulent entrainment process, focusing in particular on their relation to small-scale processes in the proximity of the turbulent/non-turbulent interface (TNTI). Three-dimensional particle tracking velocimetry (3D-PTV) measurements of an axisymmetric jet are compared to data from a direct numerical simulation (DNS) of a zero-mean-shear (ZMS) flow. First, conditional statistics relative to the interface position are investigated in a pseudoEulerian view (i.e. in a fixed frame relative to the interface position) and in a Lagrangian view. We find that in a pseudo-Eulerian frame of reference, both vorticity fluctuations and mean shear contribute to the vorticity jump at the boundary between irrotational and turbulent regions. In contrast, the Lagrangian evolution of enstrophy along trajectories crossing the entrainment interface is almost exclusively dominated by vorticity fluctuations, at least during the first Kolmogorov time scales after passing the interface. A mapping between distance to the instantaneous interface versus conditional time along the trajectory shows that entraining particles remain initially close to the TNTI and therefore attain lower average enstrophy values. The ratio between the rate of change of enstrophy in the two frames of references defines the local entrainment velocity v n = −(Dω 2 /Dt)/(∂ω 2 /∂x n ), where ω 2 is enstrophy andx n is the coordinate normal to the TNTI. The quantity v n is decomposed into mean and fluctuating components and it is found that mean shear enhances the local entrainment velocity via inviscid and viscous effects. Further, the analysis substantiates that for all investigated flow configurations the local entrainment velocity depends considerably on the geometrical shape of the interface. Depending on the surface shape, different small-scale mechanisms are dominant for the local entrainment process, i.e. viscous effects for convex shapes and vortex stretching for concave shapes, looking from the turbulent region towards the convoluted boundary. Moreover, turbulent fluctuations display a stronger dependence on the shape of the interface than mean shear effects.

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Evaluation of Various Turbulence Models in Predicting Airflow and Turbulence in Enclosed Environments by CFD: Part 1—Summary of Prevalent Turbulence Models

Zhai

Zhang²,

Zhang³

et al. 2007

HVAC&R Research

379

126

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Behaviour of turbulence models near a turbulent/non-turbulent interface revisited

Cited by 6 publications

References 10 publications

Prediction of Separation-Induced Transition on the SD7003 Airfoil Using Algebraic Transition Triggering

Prediction of Separation-Induced Transition on the SD7003 Airfoil Using Algebraic Transition Triggering

Effects of mean shear on the local turbulent entrainment process

Evaluation of Various Turbulence Models in Predicting Airflow and Turbulence in Enclosed Environments by CFD: Part 1—Summary of Prevalent Turbulence Models

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