Modeling the response of turbulence subjected to cyclic irrotational strain

Hadžić, I.; Hanjalić, K.; Laurence, Dominique

doi:10.1063/1.1366677

Cited by 26 publications

(15 citation statements)

References 4 publications

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“…Somewhat similar frequency-dependent nonequilibrium features have also been observed in turbulence subjected to time-varying plane strain. 6,7 While the computational burden of DNS necessarily limits the extent of any detailed parametric study of periodically sheared turbulence dynamics, accurate second-order RANS closures could, in principle, allow a more extensive parametric investigation. In general, however, accurate prediction of nonequilibrium dynamics in the anisotropy and energetics of turbulence poses a significant challenge for turbulence modeling.…”

Section: ͑1͒mentioning

confidence: 99%

Frequency response of periodically sheared homogeneous turbulence

Hamlington

Dahm

2009

Physics of Fluids

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A detailed parametric study is presented for the dynamics of initially isotropic homogeneous turbulence subjected to periodic shear with magnitude S and frequency . The study is based on a quasianalytical solution to the anisotropy transport equation, which is shown to provide results for the shear anisotropy in this flow that agree well with direct numerical simulation ͑DNS͒, and for some key aspects of the dynamics agree better than do the most widely used second-order moment closures. The present analytical approach allows a more detailed parametric study than is practical via DNS, and provides direct insights into the parametric origins of the resulting dynamics. The long-time limit form of the shear anisotropy provides an analytical expression for the phase lag. The general solution also provides simple scalings in the full equilibrium limit as well as in the quasiequilibrium and saturated nonequilibrium regimes. The transition to the saturated nonequilibrium regime is shown to occur over a narrow range of around a critical frequency cr , for which an analytical expression is also obtained. The fundamental change in the dynamics of the turbulence kinetic energy k͑t͒ and the turbulence relaxation time scale ⌳͑t͒ as increases beyond cr is additionally addressed.

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Section: ͑1͒mentioning

confidence: 99%

Frequency response of periodically sheared homogeneous turbulence

Hamlington

Dahm

2009

Physics of Fluids

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“…The idea at the origin of the development of the C as model stems from an analytical study of the dramatic differences between the behaviour of an eddy viscosity model and an RSM in cyclic homogeneous strain [12].…”

Section: Cyclic Homogeneous Shearmentioning

confidence: 99%

“…Motivated by work on cyclic piston engines by Hadzić et al [12], the C as model builds upon existing two equation models, adding a third transport equation that is sensitive to the local stress-strain misalignment of turbulent flows. It thus aims to account for some of the features that could be captured by a more expensive stress transport model, but with only a relatively small increase in computational cost.…”

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confidence: 99%

Turbulence Modelling of Unsteady Turbulent Flows Using the Stress Strain Lag Model

Revell

Craft

Laurence

2010

Flow Turbulence Combust

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This paper reports the application of a recently developed turbulence modelling scheme known as the C as model. This model was specifically developed to capture the effects of stress-strain misalignment observed in turbulent flows with mean unsteadiness. Earlier work has reported the approach applied within a linear k-ε modelling framework, and some initial testing of it within the k-ω SST model of Menter (AIAA J 32:1598(AIAA J 32: -1605(AIAA J 32: , 1994. The resulting k-ε-C as and SST-C as models have been shown to result in some of the advantages of a full Reynolds Stress transport Model (RSM), whilst retaining the computational efficiency and stability benefits of a eddy viscosity model (EVM). Here, the development of the the high-Reynolds-number version of the C as model is outlined, with some example applications to steady and unsteady homogeneous shear flows. The SST-C as form of the model is then applied to further, more challenging cases of 2-D flow around a NACA0012 aerofoil beyond stall and the 3-D flow around a circular cylinder in a square duct, both being flows which exhibit large, unsteady, separated flow regions. The predictions returned by a range of other common turbulence modelling schemes are included for comparison and the SST-C as scheme is shown to return generally good results, comparable in some respects to those obtainable from far more complex schemes, for only moderate computing resource requirements.

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“…15, which is in turn at the origin of the wrong prediction of the peak velocities, as shown in Section 4.2. Therefore, the stress-strain lag, whose role was emphasized by Hadžić et al (2001) in the case of homogeneous turbulence subjected to periodic compression-dilatation strains, also plays a fundamental role in the present flow.…”

Section: Misalignment Of the Strain And Anisotropy Tensorsmentioning

confidence: 95%

“…It is well known that negative production results from a misalignment of the proper axes of the strain and anisotropy tensors: in particular, in flows subjected to periodic irrotational strains, a time lag is observed between these two tensors, which is at the origin of a turbulence decay (see, e.g., Hadžić et al, 2001). The strain and anisotropy tensors are both 3 · 3 symmetrical tensors: the eigenvectors form orthogonal bases.…”

Section: Misalignment Of the Strain And Anisotropy Tensorsmentioning

confidence: 98%

Turbulence modelling of statistically periodic flows: Synthetic jet into quiescent air

Carpy

Manceau

2006

International Journal of Heat and Fluid Flow

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Computations of a 2D synthetic jet are performed with usual RANS equations solved in time-accurate mode (URANS), with the standard k-e model and the Rotta + IP second moment closure. The purpose of the present work is to investigate the ability of these standard turbulence models to close the phase-averaged Navier-Stokes equations. Results are compared with recent experiments by Yao et al. made available to the CFD Validation of Synthetic Jets and Turbulent Separation Control workshop held in Williamsburg in 2004. Comparisons of the performance of the models with experimental data show that the evolution of the vortex dipole generated by inviscid mechanisms is not correctly reproduced by the k-e model. The Reynolds-stress model gives much more realistic predictions. However, several characteristics are not well predicted, as for instance the convection velocity. A detailed analysis shows that the vortex dipole dynamics is essentially inviscid during the early blowing phase, when the flow is more transitional than fully turbulent. Turbulence develops and influences the dynamics of the vortices only at a later stage of the blowing phase. Consequently, it is of importance that the turbulence models do not predict erroneously high levels of turbulence. In particular, the present study shows that the correct prediction of the region of negative production that appears during the deceleration of the blowing velocity, due to the misalignment of the strain and anisotropy tensors, is crucial. Therefore, linear eddy-viscosity models must be discarded for this type of pulsed flows, in particular for flow control using synthetic jets.

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Modeling the response of turbulence subjected to cyclic irrotational strain

Cited by 26 publications

References 4 publications

Frequency response of periodically sheared homogeneous turbulence

Frequency response of periodically sheared homogeneous turbulence

Turbulence Modelling of Unsteady Turbulent Flows Using the Stress Strain Lag Model

Turbulence modelling of statistically periodic flows: Synthetic jet into quiescent air

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