Shear-improved Smagorinsky model for large-eddy simulation of wall-bounded turbulent flows

Lévêque, Emmanuel; Toschi, Federico; Shao, Lei; Bertoglio, Jean-Pierre

doi:10.1017/s0022112006003429

Cited by 172 publications

(123 citation statements)

References 45 publications

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“…In the context of large-eddy simulations, this has been done with the shear-improved sub-grid-scale models in the Eulerian framework (Lévêque et al, 2007). Future ocean experiments focusing on the dispersion properties of tracers having vertical structures, such as the chlorophyll field, are needed to reveal more about the dynamics and statistics at those spatial scales where shear might dominate.…”

Section: Discussionmentioning

confidence: 99%

Effects of vertical shear in modelling horizontal oceanic dispersion

et al. 2016

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Abstract. The effect of vertical shear on the horizontal dispersion properties of passive tracer particles on the continental shelf of the South Mediterranean is investigated by means of observation and model data. In situ current measurements reveal that vertical gradients of horizontal velocities in the upper mixing layer decorrelate quite fast ( ∼ 1 day), whereas an eddy-permitting ocean model, such as the Mediterranean Forecasting System, tends to overestimate such decorrelation time because of finite resolution effects. Horizontal dispersion, simulated by the Mediterranean sea Forecasting System, is mostly affected by: (1) unresolved scale motions, and mesoscale motions that are largely smoothed out at scales close to the grid spacing; (2) poorly resolved time variability in the profiles of the horizontal velocities in the upper layer. For the case study we have analysed, we show that a suitable use of deterministic kinematic parametrizations is helpful to implement realistic statistical features of tracer dispersion in two and three dimensions. The approach here suggested provides a functional tool to control the horizontal spreading of small organisms or substance concentrations, and is thus relevant for marine biology, pollutant dispersion as well as oil spill applications.

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Section: Discussionmentioning

confidence: 99%

Effects of vertical shear in modelling horizontal oceanic dispersion

et al. 2016

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“…An abundant number of prescriptions are possible for the parameterization of these SGS fluxes, [e.g., Kosović (1997), Bou-Zeid et al (2005), Bhushan and Warsi (2005), Lévêque et al (2007), and Ramachandran and Wyngaard (2011) to mention just a few]. For simplicity and because of the flow regime of interest, we adopt the two-part SGS model proposed by Sullivan et al (1994) that utilizes the transport equation in (1c) and an eddy viscosity approach in the parameterization of the SGS fluxes given by (2).…”

Section: Les Equationsmentioning

confidence: 99%

Turbulent Winds and Temperature Fronts in Large-Eddy Simulations of the Stable Atmospheric Boundary Layer

Sullivan

Weil

Patton

et al. 2016

Journal of the Atmospheric Sciences

120

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The nighttime high-latitude stably stratified atmospheric boundary layer (SBL) is computationally simulated using high-Reynolds number large-eddy simulation on meshes varying from 200 3 to 1024 3 over 9 physical hours for surface cooling rates C r 5 [0.25, 1] K h 21 . Continuous weakly stratified turbulence is maintained for this range of cooling, and the SBL splits into two regions depending on the location of the lowlevel jet (LLJ) and C r . Above the LLJ, turbulence is very weak and the gradient Richardson number is nearly constant: Ri ; 0:25. Below the LLJ, small scales are dynamically important as the shear and buoyancy frequencies vary with mesh resolution. The heights of the SBL and Ri noticeably decrease as the mesh is varied from 200 3 to 1024 3 . Vertical profiles of the Ozmidov scale L o show its rapid decrease with increasing C r , with L o , 2 m over a large fraction of the SBL for high cooling. Flow visualization identifies ubiquitous warm-cool temperature fronts populating the SBL. The fronts span a large vertical extent, tilt forward more so as the surface cooling increases, and propagate coherently. In a height-time reference frame, an instantaneous vertical profile of temperature appears intermittent, exhibiting a staircase pattern with increasing distance from the surface. Observations from CASES-99 also display these features. Conditional sampling based on linear stochastic estimation is used to identify coherent structures. Vortical structures are found upstream and downstream of a temperature front, similar to those in neutrally stratified boundary layers, and their dynamics are central to the front formation.

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“…In figure 5, the vorticity is plotted, and the strongly vortical flow at the outflow after the porous medium is clearly visible. As the flow is strongly wall bounded, a dynamic turbulence model such as presented by Lévêque et al [15] will be applied.…”

Section: Preliminary Results For the Flow Through Porous Mediummentioning

confidence: 99%

Towards aeroacoustic sound generation by flow through porous media

Hasert

Bernsdorf

Roller

2011

Phil. Trans. R. Soc. A.

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In this work, we present single-step aeroacoustic calculations using the Lattice Boltzmann method (LBM). Our application case consists of the prediction of an acoustic field radiating from the outlet of a porous media silencer. It has been proved that the LBM is able to simulate acoustic wave generation and propagation. Our particular aim is to validate the LBM for aeroacoustics in porous media. As a validation case, we consider a spinning vortex pair emitting sound waves as the vortices rotate around a common centre. Non-reflective boundary conditions based on characteristics have been adopted from Navier-Stokes methods and are validated using the time evolution of a Gaussian pulse. We show preliminary results of the flow through the porous medium.

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Shear-improved Smagorinsky model for large-eddy simulation of wall-bounded turbulent flows

Cited by 172 publications

References 45 publications

Effects of vertical shear in modelling horizontal oceanic dispersion

Effects of vertical shear in modelling horizontal oceanic dispersion

Turbulent Winds and Temperature Fronts in Large-Eddy Simulations of the Stable Atmospheric Boundary Layer

Towards aeroacoustic sound generation by flow through porous media

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