Large Eddy Simulation of Flows of Engineering Interest: A Review

Sarkar, S.

doi:10.1007/978-981-15-2670-1_11

Cited by 4 publications

(4 citation statements)

References 77 publications

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“…Second, the cumulative number of papers that addressed modeling issues shows that there is a very limited number of attempts (a total of 15 papers according to this search, which may give only a partial impression) to address the typical modeling issues of popular hybrid RANS-LES methods. Correspondingly, the predominant opinion of the community in this regard is "There exist two kinds of LES-RANS hybrid methodology: one is WMLES and the other being detached-eddy simulation (DES)" [53].…”

Section: Model Eqsmentioning

confidence: 99%

“…In this approach, the RANS is applied only to a thin layer near the wall, where the layer thickness may be much smaller than the boundary layer thickness. This method captures most of the turbulence inside the boundary layer by the LES without resolving the smallest scales above the viscous sublayer [53]. However, the concept of the WMLES faces issues.…”

Section: The Cfd Dilemmamentioning

confidence: 99%

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A Mathematical Solution to the Computational Fluid Dynamics (CFD) Dilemma

Stefan

2023

Mathematics

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Turbulent flows of practical relevance are often characterized by high Reynolds numbers and solid boundaries. The need to account for flow separation seen in such flows requires the use of (partially) resolving simulation methods on relatively coarse grids. The development of such computational methods is characterized by stagnation. Basically, only a few methods are regularly applied that are known to suffer from significant shortcomings: such methods are often characterized by the significant uncertainty of the predictions due to a variety of adjustable simulation settings, their computational cost can be essential because performance shortcomings need to be compensated by a higher resolution, and there are questions about their reliability because the flow resolving ability is unclear; hence, all such predictions require justification. A substantial reason for this dilemma is of a conceptual nature: the lack of clarity about the essential questions. The paper contrasts the usually applied simulation methods with the minimal error simulation methods presented recently. The comparisons are used to address essential questions about the required characteristics of the desired simulation methods. The advantages of novel simulation methods (including their simplicity, significant computational cost reductions, and controlled resolution ability) are pointed out.

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Section: Model Eqsmentioning

confidence: 99%

Section: The Cfd Dilemmamentioning

confidence: 99%

A Mathematical Solution to the Computational Fluid Dynamics (CFD) Dilemma

Stefan

2023

Mathematics

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“…The flow is considered to be saltwater with

ρ = 1030

kg m −3 and

μ = 0.00105

Pa s. The average velocity field is calculated after the flow reaches a statistically steady solution. The time averaging period is set to 200 s after this time point, which comprises 7–15 particles passes through the effective length of the geometry (Sarkar 2020). The 2D turbulent kinetic energy k 2D CFD is calculated to compare with the experimental results.…”

Section: Materials and Proceduresmentioning

confidence: 99%

An experimental Stommel Retention Zone facility with an application to oil droplet dispersion

Gurung

Smith

Zeidi

et al. 2022

Limnology & Ocean Methods

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Stommel Retention Zones (SRZs) associated with wind-driven Langmuir circulation (LC) facilitate the subsurface retention of particles and thus affect processes such as oil spill dispersion, sediment suspension, oil-particle aggregation, and plankton distribution. Since the effect of SRZs on these processes is difficult to study in the field, we present a novel laboratory facility designed to recreate the counterrotating vortex pair flow pattern associated with small-scale SRZs of various strengths in two dimensions (2D). We then inject an oil jet into this facility to study buoyant oil droplet retention in these SRZs. 2D particle image velocimetry and hybrid Reynolds-averaged Navier-Stokes/large eddy simulation are used to characterize the flow. Large-scale oil droplet trajectories in the SRZs are visualized, and oil droplet statistics in the downwelling region and vortex core are measured using high-magnification brightfield imaging and a droplet detection algorithm. Values of maximum velocity (7.7-32.2 mm s À1 ), turbulent kinetic energy (10 À6 to 10 À4 m 2 s À2 ), and turbulent kinetic energy dissipation rate (10 À7 to 10 À5 m 2 s À3 ) in the downwelling region of the facility fall within the range of values observed in the field. Flow field strength strongly influences oil droplet trajectories, the shape and size of the SRZ, and oil droplet statistics over time, with stronger flows retaining larger oil droplets in the downwelling region over longer periods of time. Indeed, droplets of almost 400 μm diameter are observed in the downwelling region after almost 10 min for the strongest flow. The facility may be used to study the behavior of microplastics, sediments, and zooplankton in LC in the future.

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“…Different strategies exist to compute turbulent reacting flow problems depending on the level of resolution or modeling of the turbulence structures: Direct Numerical Simulations (DNS), Large Eddy Simulations (LES) and Reynolds Averaged Navier Stokes Fuels 2021, 2 (RANS). In DNS all turbulence scales are explicitly computed, in LES only the larger scale motions are resolved on the numerical grid and the smaller scale motions are accounted for by a subgrid scale (SGS) model [10], and in RANS only mean flow fields are resolved [11]. LES is a well developed approach [12] which offers a substantial decrease with respect to DNS [13], a non exhaustive list for the interested reader includes the work in [14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Non-Premixed Filtered Tabulated Chemistry: Filtered Flame Modeling of Diffusion Flames

Vega

Coussement

Sadiki

et al. 2021

Fuels

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The flame front filtering is a well-known strategy in turbulent premixed combustion. An extension of this approach for the non-premixed combustion context has been proposed by means of directly filtering counterflow diffusion flamelets. Promising results were obtained for the non-premixed filtered tabulated chemistry formalism on 1-D and 2-D unresolved counterflow flame configurations. The present paper demonstrates the soundness of this approach on a 3-D real laminar non-premixed coflow flame. The model results are compared against the direct filtering of the fully resolved laminar diffusion flame showing that the formalism adequately describes the underlying physics. The study reveals the importance of the one-dimensional counterflow flamelet hypothesis, so that the model activation under this condition is ensured by means of a flame sensor. The consistent coupling between the model and the flame sensor adequately retrieves the flame lift-off and satisfactorily predicts the profile extension due to the filtering process.

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Large Eddy Simulation of Flows of Engineering Interest: A Review

Cited by 4 publications

References 77 publications

A Mathematical Solution to the Computational Fluid Dynamics (CFD) Dilemma

A Mathematical Solution to the Computational Fluid Dynamics (CFD) Dilemma

An experimental Stommel Retention Zone facility with an application to oil droplet dispersion

Non-Premixed Filtered Tabulated Chemistry: Filtered Flame Modeling of Diffusion Flames

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