Partially-averaged Navier-Stokes method for turbulent flows: k-w model implementation

Lakshmipathy, Sunil; Girimaji, Sharath S.

doi:10.2514/6.2006-119

Cited by 51 publications

(32 citation statements)

References 9 publications

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“…(6) as shown in details by Girimaji (2006) and Lakshmipathy and Girimaji (2006). Therefore, a PANS model can be derived from any parent RANS model based on the ratio between unresolved and total turbulence quantities.…”

Section: Model Formulationmentioning

confidence: 99%

“…Therefore, a PANS model can be derived from any parent RANS model based on the ratio between unresolved and total turbulence quantities. The original PANS model (Girimaji, 2006) was derived based on the standard k-e model, while Lakshmipathy and Girimaji (2006) suggested PANS equations based on the k-x model. Later, a near-wall formulation of PANS was proposed by Basara et al (2011) in the form of the PANS k-e-f-f model, and a low Reynolds number variant of PANS was developed by Ma et al (2011) using the low-Reynolds number k-e model of Abe et al (1994).…”

Section: Model Formulationmentioning

confidence: 99%

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A partially-averaged Navier–Stokes model for the simulation of turbulent swirling flow with vortex breakdown

Foroutan

Yavuzkurt

2014

International Journal of Heat and Fluid Flow

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a b s t r a c tThis paper presents the development and validation of a new partially-averaged Navier-Stokes (PANS) model which can successfully predict turbulent swirling flow with vortex breakdown. The proposed PANS model uses an extended low Reynolds number k-e model as the baseline model. Furthermore, a new formulation for the unresolved-to-total turbulent kinetic energy ratio f k is developed using partial integration of the complete turbulence energy spectrum. Therefore, the present formulation of f k is believed to be superior to the previously used constant or computed values. The newly developed PANS model is used in unsteady numerical simulations of two turbulent swirling flows containing vortex breakdown, namely swirling flow through an abrupt expansion and flow in a draft tube of a hydraulic turbine operating under partial load. The present PANS model accurately predicts time-averaged and root-mean-square (rms) velocities in the case of the abrupt expansion, while it is shown to be superior to the Delayed Detached Eddy Simulation (DDES) and Shear Stress Transport (SST) k-x models. Predictions of the reattachment length using the present model shows at least 14% and 23% improvements compared to the DDES and the SST k-x models respectively. Also, transient features of the flow, e.g. vortex rope formation and precession, is well captured in the case of the complex draft tube flow. The frequency of the vortex rope precession, which causes severe fluctuations and vibrations, is well predicted by only 7% deviations from the experimental data.

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Section: Model Formulationmentioning

confidence: 99%

Section: Model Formulationmentioning

confidence: 99%

A partially-averaged Navier–Stokes model for the simulation of turbulent swirling flow with vortex breakdown

Foroutan

Yavuzkurt

2014

International Journal of Heat and Fluid Flow

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“…Hence, variations of these parameters was tested (Table 2). Regarding turbulence models, 3 different approaches were applied -classical RANS one using AVL's 3-euqation k-z-f model [1,2,3], the LES one [4,5,6,7,8,14] using Smagorinsky model (and in some cases, dynamic LES-CSM one) and the PANS one [9,10,11]. Concerning boundary conditions, they correspond to measurement setup -the most important one is the pressure difference between inlet and outlet, which was constant at the value of 5 kPa for all cases.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…However, one of possible disadvantages is that PANS (as it is implemented in [14]) can be applied to steady cases from statistical point of view (e.g., steady flow test bench) -it will not work properly if unsteady case is considered. Details regarding the PANS approach can be found in [9,10,11].…”

Section: Appendixmentioning

confidence: 99%

Application of Les, Pans and Rans to a Case of Intake Channel Steady Flow Test Bench

Vítek¹,

Tichánek²,

Hatschbach³

2015

Journal of Middle European Construction and Design of Cars

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SHRNUTÍČlánek se zabývá vyhodnocením průtokových vlastností (průtokový součinitel, součinitel příčné a tečné rotace) sacího kanálu užitím jak 3-D CFD simulace, tak měření. Byla provedena citlivostní studie různých parametrů simulace. Nejdůležitější jsou vlastnosti sítě a použité modely turbulence (uvažované modely: LES, PANS a RANS). Co se týká sítě, tak kritickým parametrem je konfigurace v těsné blízkosti stěny -tloušťka a počet vrstev těsně u stěny mají velký vliv na průtok, avšak součinitele příčné a tečné rotace na tom téměř nezávisí. Odtud plyne, že tyto parametry sítě lze považovat za ladící parametry CFD modelu. Co se týká velikosti oka sítě, 2 velikosti byly testovány (0.6 a 0.3 mm). Ukázalo se, že ani jedna z těchto sítí není dostatečně jemná pro korektní aplikaci LES. A tedy PANS funguje spíše jako RANS. Z hlediska modelů turbulence je PANS jeví jako nejlepší možnost, protože kombinuje výhody jak LES, tak RANS. Obecně je možné konstatovat, že lze dosáhnout relativně dobré shody na průtoku, ale součinitele příčné a tečné rotace jsou problematické, neboť byla dosažena pouze kvalitativní shoda. KLÍČOVÁ SLOVA: PRŮTOKOVÝ SOUČINITEL, ČÍSLO TEČNÉ ROTACE, ČÍSLO PŘÍČNÉ ROTACE, MODELOVÁNÍ TURBULENCE, LES, PANS, RANS ABSTRACTThe paper deals with evaluation of intake channel flow properties (discharge coefficient, tumble and swirl ratio) using both 3-D CFD simulation and measurement. Sensitivity of different calculation parameters was tested. The most important ones are mesh parameters and applied turbulence models (considered models: LES, PANS and RANS). Concerning the mesh, the critical parameter is a mesh configuration near a wall -a thickness of mesh boundary layer and an amount of these layers have significant impact on mass flow rate while tumble/swirl ratio is unaffected by that. Based on that, these mesh parameters can be considered as tuning constants for fine-tuning the CFD model. Regarding the mesh cell size, 2 different values were tested (0.6 and 0.3 mm). It was found out that neither mesh is fine enough to perform proper LES. Hence, PANS performance is close to RANS. Concerning the turbulence models, PANS seems to be the best one as it combines advantages of both LES and RANS. Generally speaking, mass flow rate prediction is relatively good while swirl/tumble one is more problematic as only qualitative agreement can be achieved.

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“…The PANS model changes seamlessly from RANS to the direct numerical solution (DNS) of the NavierStokes equations and is purported to provide the best possible physical fidelity on any given numerical grid. Lakshmipathy and Girimaji [2] used PANS based on the k − ε turbulence model to simulate the flow past a circular cylinder.…”

Section: Introductionmentioning

confidence: 99%

Partially-Averaged Navier–Stokes simulations of flows around two different Ahmed bodies

2015

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Partially-averaged Navier-Stokes method for turbulent flows: k-w model implementation

Cited by 51 publications

References 9 publications

A partially-averaged Navier–Stokes model for the simulation of turbulent swirling flow with vortex breakdown

A partially-averaged Navier–Stokes model for the simulation of turbulent swirling flow with vortex breakdown

Application of Les, Pans and Rans to a Case of Intake Channel Steady Flow Test Bench

Partially-Averaged Navier–Stokes simulations of flows around two different Ahmed bodies

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