Current trends in modelling research for turbulent aerodynamic flows

Gatski, Thomas B.; Rumsey, Christopher L.; Manceau, Rémi

doi:10.1098/rsta.2007.2015

Cited by 44 publications

(32 citation statements)

References 80 publications

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“…In this case, they are qualified as self-consistent. As shown by Gatski et al [8], a framework can be established for self-consistent hybrid RANS-LES methodologies by defining the general filtering operator…”

Section: Self-consistent Hybrid Methodsmentioning

confidence: 99%

“…Such a spatial framework easily provides a formalism for hybrid RANS/LES methods in the case of homogeneous turbulence, since Reynolds averaging is then equivalent to spatial averaging, i.e., to spatial filtering in the limit of infinite filter widths. In the more general and useful case of inhomogeneous, stationary turbulence, in order to formulate a seamless hybrid methodology, a time filtering operator can be defined [8], with a filter kernel of the form…”

Section: Self-consistent Hybrid Methodsmentioning

confidence: 99%

“…However, in the frame of inhomogeneous turbulent flows, a trait, common among most of the hybrid RANS/LES approaches proposed so far, is the inherent difference between variables obtained from spatially filtered instantaneous variables and variables obtained from long-time averaged instantaneous variables, with the latter being representative of an ensemble averaged variable through an ergodic hypothesis [8]. This problem is a strong limitation to the understanding and modeling of the physical interaction mechanisms in the intermediate regions that are not clearly RANS or LES regions, and consequently suffer from an ambiguous defini-tion of the variables of the model.…”

Section: Introductionmentioning

confidence: 99%

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Toward an equivalence criterion for Hybrid RANS/LES methods

2015

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A criterion is established to assess the equivalence between hybrid RANS/LES methods, called H-equivalence, based on the modeled energy of the unresolved scales, which leads to similar low-order statistics of the resolved motion. Different equilibrium conditions are considered, and perturbation analyses about the equilibrium states are performed. The procedure is applied to demonstrate the equivalence between two particular hybrid methods, and leads to relationships between hybrid method parameters that control the partitioning of energy between the resolved and unresolved scales of motion. This equivalence is validated by numerical results obtained for the cases of plane and periodically constricted channel flows. This concept of H-equivalence makes it possible to view different hybrid methods as models for the same system of equations: as a consequence, detached-eddy simulation (DES), which is shown to be H-equivalent to the temporal partially integrated transport model (T-PITM) in inhomogeneous, stationary situations, can be interpreted as a model for the subfilter stress involved in the temporally filtered Navier-Stokes equations.

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Section: Self-consistent Hybrid Methodsmentioning

confidence: 99%

Section: Self-consistent Hybrid Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Toward an equivalence criterion for Hybrid RANS/LES methods

2015

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“…Obviously, at the high Reynolds numbers experienced with most aerospace flows, turbulence modelling is a key issue and so the review of Gatski et al (2007) is dedicated to this important area. The modelling of complex time-varying turbulent structures that involve a large range of temporal and spatial scales (the smallest of which is the Kolmogorov microscale) has always been the weak link in the numerical prediction of fluid flows.…”

Section: Turbulencementioning

confidence: 99%

“…This theme issue has papers in the following areas: turbulence (Gatski et al 2007); flow/turbulence control (Carpenter et al 2007); propulsive jet dynamics and noise (Birch et al); aeroengine external air systems (Dawes 2007); aeroengine internal air systems (Chew & Hills 2007); aeroelasticity for aeroengines and external aerodynamics (Bartels & Sayma 2007); design optimization (Keane & Scanlan 2007); and unsteady flow modelling (Hassan et al 2007). …”

Section: Introductionmentioning

confidence: 99%

Introduction. Computational aerodynamics

Tucker

2007

Phil. Trans. R. Soc. A.

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The wide range of uses of computational fluid dynamics (CFD) for aircraft design is discussed along with its role in dealing with the environmental impact of flight. Enabling technologies, such as grid generation and turbulence models, are also considered along with flow/turbulence control. The large eddy simulation, Reynolds-averaged NavierStokes and hybrid turbulence modelling approaches are contrasted. The CFD prediction of numerous jet configurations occurring in aerospace are discussed along with aeroelasticity for aeroengine and external aerodynamics, design optimization, unsteady flow modelling and aeroengine internal and external flows. It is concluded that there is a lack of detailed measurements (for both canonical and complex geometry flows) to provide validation and even, in some cases, basic understanding of flow physics. Not surprisingly, turbulence modelling is still the weak link along with, as ever, a pressing need for improved (in terms of robustness, speed and accuracy) solver technology, grid generation and geometry handling. Hence, CFD, as a truly predictive and creative design tool, seems a long way off. Meanwhile, extreme practitioner expertise is still required and the triad of computation, measurement and analytic solution must be judiciously used.

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In‐Cylinder Flow

Borée

Miles

2014

Encyclopedia of Automotive Engineering

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The general properties and evolution of in‐cylinder flows are reviewed, from the initial generation of turbulence and large‐scale bulk structures during the induction process until the early expansion stroke period, when flow processes continue to aid with the completion of combustion. Flows typical of both spark ignition and compression ignition engine technologies are described. Our primary emphasis is on providing the practicing engineer and engine designer with a physical understanding of the storage of flow energy in large‐scale rotating structures; the mechanisms by which this energy can be extracted to enhance turbulent mixing processes; the interaction of these flow structures with the compression, fuel injection, and combustion processes; and the fluid‐dynamical origin of cycle‐to‐cycle fluctuations in the combustion process. We further examine characteristics of the turbulence, with the objective of providing engineers with a natural understanding of how turbulence scales relate to engine parameters (bore, stroke, speed, etc.) and of how turbulence is generated and dissipated throughout the engine cycle. Various methods used to characterize and separate the turbulence from large‐scale, coherent cycle‐to‐cycle fluctuations in the flow, and tools to characterize the topology of the flow, are also briefly reviewed. Lastly, we identify several areas, principally related to turbulence generation and dissipation in engines, to the elucidation of flow structures and their cycle‐to‐cycle variation, and to near‐wall flows, that are still poorly understood and that would benefit from additional investigations by the research community.

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Current trends in modelling research for turbulent aerodynamic flows

Cited by 44 publications

References 80 publications

Toward an equivalence criterion for Hybrid RANS/LES methods

Toward an equivalence criterion for Hybrid RANS/LES methods

Introduction. Computational aerodynamics

In‐Cylinder Flow

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