A fractal model for large eddy simulation of turbulent flow

Scotti, Alberto; Meneveau, Charles

doi:10.1016/s0167-2789(98)00266-8

Cited by 84 publications

(100 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is the purpose of this work to extend the approach of [6,7] in terms of realistic turbulence-like signal generation with all the aforementioned desirable characteristics and demonstrate its potential for LES through a-priori analysis (an LES-SGS model evaluation framework). We will also demonstrate the competence of our scheme in the emulation of passive-scalar fields for which the non-Gaussian pdf and multiaffinity are significantly pronounced and cannot be ignored.…”

Section: Lesmentioning

confidence: 99%

“…Several schemes have been proposed [1,2,3,4,5] with different degrees of success in reproducing various characteristics of turbulence. Recently, Scotti and Meneveau [6,7] further broadened the scope of synthetic turbulence research by demonstrating its potential in computational modeling. Their innovative turbulence emulation scheme based on the Fractal Interpolation Technique (FIT) [8,9] was found to be particularly amenable for a specific type of turbulence modeling, known as LargeEddy Simulation (LES, at present the most efficient technique available for high Reynolds number flow simulations, in which the larger scales of motion are resolved explicitly and the smaller ones are modeled).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthetic turbulence, fractal interpolation, and large-eddy simulation

2004

View full text Add to dashboard Cite

Fractal Interpolation has been proposed in the literature as an efficient way to construct closure models for the numerical solution of coarse-grained Navier-Stokes equations. It is based on synthetically generating a scale-invariant subgrid-scale field and analytically evaluating its effects on large resolved scales. In this paper, we propose an extension of previous work by developing a multiaffine fractal interpolation scheme and demonstrate that it preserves not only the fractal dimension but also the higher-order structure functions and the non-Gaussian probability density function of the velocity increments. Extensive a-priori analyses of atmospheric boundary layer measurements further reveal that this Multiaffine closure model has the potential for satisfactory performance in large-eddy simulations. The pertinence of this newly proposed methodology in the case of passive scalars is also discussed.

show abstract

Section: Lesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthetic turbulence, fractal interpolation, and large-eddy simulation

2004

View full text Add to dashboard Cite

show abstract

“…By the time the incoming fluid reaches the front of the gravity current, nonlinear interactions turn the artificial noise into "real" turbulence (Scotti and Meneveau, 1999). The amplitude of the noise was set so that the rms intensity of the resulting turbulent fluctuations just upstream of the head was about 0.5% of the speed of propagation of the gravity current, corresponding to the value reported in the experiments of Britter and Simpson (1978).…”

Section: Discussionmentioning

confidence: 99%

Plankton accumulation and transport in propagating nonlinear internal fronts

Scotti¹,

Pineda²

2007

J Mar Res

Self Cite

View full text Add to dashboard Cite

Accumulation and transport of plankton in fronts propagating across-shore is a process of considerable ecological importance for many inhabitants of the littoral zone, since it links the offshore larval pool with the juvenile and adult inshore habitat. Several field studies have shown that larval plankton accumulates in fronts, but have failed to give a conclusive proof that effective Lagrangian transport takes place. A few process-oriented numerical studies have lent support to the idea, but the scope of their results is limited by the two-dimensional nature of the flows considered and by the simple model used to account for the behavior of plankton. In this paper, we relax both constraints. We solve the three-dimensional Navier-Stokes equation to compute the time dependent velocity field, and we use an empirically based model for the behavior of plankton. Our results show that accumulation and transport is possible, even for larvae characterized by sustained swimming speeds that are small compared with the speed of propagation of the front. We introduce a simple model to characterize the accumulation along the front, which includes both entrainment and detrainment. The model accurately represents accumulation calculated from the numerical runs, and provide a simple tool to estimate transport under a variety of circumstances. We also investigate the spatial distribution of plankton along and across the front and show that it is very patchy and dependent on the swimming speed of plankton, with important implications for interpreting results from field experiments.

show abstract

“…However, in more realistic situations, including turbulence near walls or in boundary layers, the energy backscatter has proven to reproduce a realistic backscatter in some situations ( [15,23]). The need for backscatter modeling also leads to the development of "stochastic" strategies, where the discarded small-scale motions are replaced by a set of random numbers, mimicking either a random force or synthetic velocity fields [7,33,17]. In many ways, these strategies resemble the strategies used to describe the dynamics of a heavy particle coupled to a thermal bath involving many degrees of freedom (the so-called Brownian motion).…”

Section: Introductionmentioning

confidence: 99%

A LES-Langevin model for turbulence

Laval¹,

Dubrulle

2006

Eur. Phys. J. B

View full text Add to dashboard Cite

We propose a new model of turbulence for use in large-eddy simulations (LES). The turbulent force, represented here by the turbulent Lamb vector, is divided in two contributions. The contribution including only subfilter fields is deterministically modeled through a classical eddy-viscosity. The other contribution including both filtered and subfilter scales is dynamically computed as solution of a generalized (stochastic) Langevin equation. This equation is derived using Rapid Distortion Theory (RDT) applied to the subfilter scales. The general friction operator therefore includes both advection and stretching by the resolved scale. The stochastic noise is derived as the sum of a contribution from the energy cascade and a contribution from the pressure. The LES model is thus made of an equation for the resolved scale, including the turbulent force, and a generalized Langevin equation integrated on a twice-finer grid. We compare the full model with several approximations. In the first one, the friction operator of the Langevin equation is simply replaced by an empirical constant, of the order of the resolved scale correlation time. In the second approximation, the integration is replaced by a condition of instantaneous adjustment to the stochastic force. In this approximation, our model becomes equivalent to the velocity-estimation model of Domaradzki et al. [7,5,8]. In the isotropic, homogeneous situations we study, both approximations provide satisfactory results, at a reduced computational cost. The model is finally validated by comparison to DNS and is tested against classical LES models for isotropic homogeneous turbulence, based on eddy viscosity. We show that even in this situation, where no walls are present, our inclusion of backscatter through the Langevin equation results in a better description of the flow.

show abstract

A fractal model for large eddy simulation of turbulent flow

Cited by 84 publications

References 62 publications

Synthetic turbulence, fractal interpolation, and large-eddy simulation

Synthetic turbulence, fractal interpolation, and large-eddy simulation

Plankton accumulation and transport in propagating nonlinear internal fronts

A LES-Langevin model for turbulence

Contact Info

Product

Resources

About