High-Pass Filtered Eddy-Viscosity Models for Large-Eddy Simulations of Compressible Wall-Bounded Flows

2004 ◽  
Author(s):  
Steffen Stolz
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Eddy Viscosity ◽  
Large Eddy Simulations ◽  
Scale Model ◽  
Subgrid Scale ◽  
Smagorinsky Model ◽  
Viscosity Models ◽  
Large Eddy ◽  
High Pass

Eddy-viscosity models such as the Smagorinsky model [1] are the most often employed subgrid-scale (SGS) models for large-eddy simulations (LES). However, for a correct prediction of the viscous sublayer of wall-bounded turbulent flows van-Driest wall damping functions or a dynamic determination of the constant [2] have to be employed. Alternatively, high-pass filtered (HPF) quantities can be used instead of the full velocity field for the computation of the subgrid-scale model terms. This approach has been independently proposed by Vreman [3] and Stolz et al. [4]. In this contribution we consider LES of a spatially developing supersonic turbulent boundary layer at a Mach number of 2.5 and momentum-thickness Reynolds numbers at inflow of approximately 4500, using the HPF Smagorinsky model. The model is supplemented by a HPF eddy-diffusivity ansatz for the SGS heat flux in the energy equation. Turbulent inflow conditions are generated by a rescaling and recycling technique proposed by [5] where the mean and fluctuating part of the turbulent boundary layer at some distance downstream of inflow is rescaled and reintroduced at inflow.

High-Pass Filtered Eddy-Viscosity Models for Large-Eddy Simulations of Compressible Wall-Bounded Flows

2005 ◽  
Vol 127 (4) ◽  
pp. 666-673 ◽  
Author(s):  
Steffen Stolz
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Correct Prediction ◽  
Smagorinsky Model ◽  
Eddy Simulation ◽  
Viscosity Models ◽  
Large Eddy ◽  
High Pass

In this contribution we consider large-eddy simulation (LES) using the high-pass filtered (HPF) Smagorinsky model of a spatially developing supersonic turbulent boundary layer at a Mach number of 2.5 and momentum-thickness Reynolds numbers at inflow of ∼4500. The HPF eddy-viscosity models employ high-pass filtered quantities instead of the full velocity field for the computation of the subgrid-scale (SGS) model terms. This approach has been proposed independently by Vreman (Vreman, A. W., 2003, Phys. Fluids, 15, pp. L61–L64) and Stolz et al. (Stolz, S., Schlatter, P., Meyer, D., and Kleiser, L., 2003, in Direct and Large Eddy Simulation V, Kluwer, Dordrecht, pp. 81–88). Different from classical eddy-viscosity models, such as the Smagorinsky model (Smagorinsky, J., 1963, Mon. Weath. Rev, 93, pp. 99–164) or the structure-function model (Métais, O. and Lesieur, M., 1992, J. Fluid Mech., 239, pp. 157–194) which are among the most often employed SGS models for LES, the HPF eddy-viscosity models do need neither van Driest wall damping functions for a correct prediction of the viscous sublayer of wall-bounded turbulent flows nor a dynamic determination of the coefficient. Furthermore, the HPF eddy-viscosity models are formulated locally and three-dimensionally in space. For compressible flows the model is supplemented by a HPF eddy-diffusivity ansatz for the SGS heat flux in the energy equation. Turbulent inflow conditions are generated by a rescaling and recycling technique in which the mean and fluctuating part of the turbulent boundary layer at some distance downstream of inflow is rescaled and reintroduced at the inflow position (Stolz, S. and Adams, N. A., 2003, Phys. Fluids, 15, pp. 2389–2412).

scholarly journals On the Application of the Dynamic Smagorinsky Model to Large-Eddy Simulations of the Cloud-Topped Atmospheric Boundary Layer

2006 ◽  
Vol 63 (2) ◽  
pp. 526-546 ◽  
Author(s):  
M. P. Kirkpatrick ◽  
A. S. Ackerman ◽  
D. E. Stevens ◽  
N. N. Mansour
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Dynamic Model ◽  
Potential Temperature ◽  
Large Eddy Simulations ◽  
Small Scale ◽  
Subgrid Scale ◽  
Smagorinsky Model ◽  
Marine Stratocumulus ◽  
Large Eddy

Abstract In this paper the dynamic Smagorinsky model originally developed for engineering flows is adapted for simulations of the cloud-topped atmospheric boundary layer in which an anelastic form of the governing equations is used. The adapted model accounts for local buoyancy sources, vertical density stratification, and poor resolution close to the surface and calculates additional model coefficients for the subgrid-scale fluxes of potential temperature and total water mixing ratio. Results obtained with the dynamic model are compared with those obtained using two nondynamic models for simulations of a nocturnal marine stratocumulus cloud deck observed during the first research flight of the second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS-II) field experiment. The dynamic Smagorinsky model is found to give better agreement with the observations for all parameters and statistics. The dynamic model also gives improved spatial convergence and resolution independence over the nondynamic models. The good results obtained with the dynamic model appear to be due primarily to the fact that it calculates minimal subgrid-scale fluxes at the inversion. Based on other results in the literature, it is suggested that entrainment in the DYCOMS-II case is due predominantly to isolated mixing events associated with overturning internal waves. While the behavior of the dynamic model is consistent with this entrainment mechanism, a similar tendency to switch off subgrid-scale fluxes at an interface is also observed in a case in which gradient transport by small-scale eddies has been found to be important. This indicates that there may be problems associated with the application of the dynamic model close to flow interfaces. One issue here involves the plane-averaging procedure used to stabilize the model, which is not justified when the averaging plane intersects a deforming interface. More fundamental, however, is that the behavior may be due to insufficient resolution in this region of the flow. The implications of this are discussed with reference to both dynamic and nondynamic subgrid-scale models, and a new approach to turbulence modeling for large-eddy simulations is proposed.

Large Eddy Simulation of Rotating Finite Source Convection

2005 ◽  
Vol 73 (1) ◽  
pp. 79-87
Author(s):  
Shari J. Kimmel-Klotzkin ◽  
Fadi P. Deek
Keyword(s):  
Large Eddy Simulation ◽  
Eddy Viscosity ◽  
Rotating Flows ◽  
Scale Model ◽  
Subgrid Scale ◽  
Smagorinsky Model ◽  
Convective Flows ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Subgrid Scale Model

Numerical simulations of turbulent convection under the influence of rotation will help understand mixing in oceanic flows. Though direct numerical simulations (DNS) can accurately model rotating convective flows, this method is limited to small scale and low speed flows. A large eddy simulation (LES) with the Smagorinsky subgrid scale model is used to compute the time evolution of a rotating convection flow generated by a buoyancy source of finite size at a relatively high Rayleigh number. Large eddy simulations with eddy viscosity models have been used successfully for other rotating convective flows, so the Smagorinsky model is a reasonable starting point. These results demonstrate that a LES can be used to model larger scale rotating flows, and the resulting flow structure is in good agreement with DNS and experimental results. These results also demonstrate that the qualitative behavior of vorticies which form under the source depend on the geometry of the flow. For source diameters that are small compared to the size of the domain, the vortices propagate away from the source. On the other hand, if the ratio of source diameter to domain size is relatively large, the vortices are constrained beneath the source. Though the results are qualitatively similar to a direct numerical simulation (DNS) and other LES, in this simulation the flow remains laminar much longer than the DNS predicts. This particular flow is complicated by the turbulence transition between the convective plume and the quiescent ambient fluid, and an eddy viscosity model is inadequate to accurately model this type of flow. In addition, the Smagorinsky model is not consistent in a noninertial reference frame. Thus the Smagorinsky model is not the optimal choice for this type of flow. In particular, the estimation model has demonstrated better results for other types of rotating flows and is the recommended subgrid scale model for future work.

scholarly journals General relativistic MHD large eddy simulations with gradient subgrid-scale model

2020 ◽  
Vol 101 (12) ◽  
Author(s):  
Daniele Viganò ◽  
Ricard Aguilera-Miret ◽  
Federico Carrasco ◽  
Borja Miñano ◽  
Carlos Palenzuela
Keyword(s):  
Large Eddy Simulations ◽  
Scale Model ◽  
Subgrid Scale ◽  
Large Eddy ◽  
General Relativistic ◽  
Subgrid Scale Model
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