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Journal ArticleDOI

Evaluation of LES models for flow over bluff body from engineering application perspective

01 Feb 2005-Sadhana-academy Proceedings in Engineering Sciences (Springer India)-Vol. 30, Iss: 1, pp 11-20

Abstract: Three SGS stress closure LES models are evaluated for turbulent flow over a square cylinder. Emphasis is placed on solving engineering-application-type problems on affordable computer resources and within reasonable turnaround times. Results are compared with available experimental data and previously published workshop results. Numerical strategies are kept the same for all the cases. Results are also discussed keeping in view limitations of LES methodology of modelling for practical problems and current developments. It is concluded that a one-equation model for subgrid kinetic energy is the best choice.
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Journal ArticleDOI
J. Ettrich, Britta Nestler1Institutions (1)
TL;DR: A coupled diffuse interface lattice Boltzmann fluid flow solver and a diffuse interface heat transfer approach are combined in view of dealing with even more convoluted geometries, incorporating the dynamics of interfaces and complex multiphysics applications.
Abstract: Diffuse interface method for heat and mass transfer simulation of cellular solids.Method for realistic modelling of complex microscale structures of cellular solids.Novel tensorial mobility approach is employed for diffuse interface heat transfer.Pore scale level CFD simulation using diffuse interface lattice Boltzmann method.Validation on complex engineering type geometries show excellent agreement. This work presents a contribution on the numerical modelling capabilities for the simulation of fluid flow and heat transfer in cellular solids - in particular we focus on open cell aluminium foams. Rather than applying one of the classical academical or commercial numerical finite volume (FV), finite difference (FD) or finite element (FE) interface tracking methods, we base our models on an interface capturing phase field method (Nestler, 2005). A coupled diffuse interface lattice Boltzmann fluid flow solver (Ettrich, 2014) and a diffuse interface heat transfer approach (Ettrich et al., 2014) are combined in view of dealing with even more convoluted geometries, incorporating the dynamics of interfaces and complex multiphysics applications. Numerical results for the combined fluid flow and heat transfer simulations in open cell metal foams are in very good agreement with experimental data (Ettrich and Martens, 2012; Ettrich et al., 2012).

21 citations

01 Jan 2009-
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16 citations

Journal ArticleDOI
Qun Wei1, Qun Wei2, Hong-xun Chen1, Zheng MaInstitutions (2)
Abstract: A non-linear eddy viscosity model (NLEVM) and a scalable hybrid Reynolds averaged Navier-Stokes/ large eddy simulation (RANS/LES) strategy are developed to improve the capability of the eddy viscosity model (EVM) to simulate complex flows featuring separations and unsteady motions To study the performance of the NLEVM, numerical simulations around S809 airfoil are carried out and the results show that the NLEVM performs much better when a large separation occurs Calculated results of the flow around a triangular cylinder show that the NLEVM can improve the precision of the flow fields to some extents, but the error is still considerable, and the small turbulence structures can not be clearly captured as the EVM Whereas the scalable hybrid RANS/LES model based on the NLEVM is fairly effective on resolving the turbulent structures and can give more satisfactory predictions of the flow fields

14 citations

Journal ArticleDOI
S. Vengadesan1, Perumal Nithiarasu2Institutions (2)
Abstract: In the late eighties and up to the beginning of nineties computation of turbulent flows is mostly dominated by RANS (Reynolds Averaged Navier-Stokes Simulation) type modelling. During the last few years URANS (Unsteady RANS) and LES (Large Eddy Simulation) type of approaches have been attempted with some success. Yet, there have been many difficulties when LES is applied to practi- cal engineering problems and to high Reynolds number flows as energy dissipating eddies become really small and mesh resolution required for a reasonably resolved LES approaches that of DNS (Direct Numerical Simulation). An alternative solu- tion suggested was to combine RANS and LES, which in general referred to as Hybrid LES. There have been many proposals for combining RANS and LES in different ways. In this article, some of the issues involved in performing hybrid LES reported in the recent literature is briefly reviewed.

9 citations

Cites methods from "Evaluation of LES models for flow o..."

  • ...In a parallel attempt, a Hybrid LES using a one-equation model for flow with massive separation was also carried out ( Vengadesan & Nakayama, 2005 )....


  • ...In a parallel attempt, a Hybrid LES using a one-equation model for flow with massive separation was also carried out (Vengadesan & Nakayama, 2005)....


Journal ArticleDOI
A. Lankadasu1, S. Vengadesan1Institutions (1)
Abstract: SUMMARY Large eddy simulation of planar shear flow past a square cylinder has been investigated. Dynamic Smagorinsky model has been used to model subgrid scale stress. The shear parameter, K, namely the nondimensional streamwise velocity gradient in the lateral direction, is 0.0, 0.1 and 0.2. Reynolds number based on the centerline velocity is fixed at Re =21400. The time and span-averaged velocity components, pressure coefficient, Reynolds stresses for uniform are in good agreement with the literature. In shear flow the calculated flow structure and mean velocity components are shown to be markedly different from those of the uniform flow. With increasing shear parameter, the cylinder wake is dominated by clockwise vortices. Both the velocity components in shear flow are compared with respective components in uniform flow. Comparison of normal and shear stresses between shear and no shear case have also been presented. Copyright q 2009 John Wiley & Sons, Ltd.

4 citations

Cites result from "Evaluation of LES models for flow o..."

  • ...Similar study from the engineering application perspective has been reported by Vengadesan and Nakayama [5]....


  • ...Nakayama and Vengadesan [6] have investigated the flow past a square cylinder by LES....


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Journal ArticleDOI
Abstract: An extended period numerical integration of a baroclinic primitive equation model has been made for the simulation and the study of the dynamics of the atmosphere's general circulation. The solution corresponding to external gravitational propagation is filtered by requiring the vertically integrated divergence to vanish identically. The vertical structure permits as dependent variables the horizontal wind at two internal levels and a single temperature, with the static stability entering as a parameter. The incoming radiation is a function of latitude only corresponding to the annual mean, and the outgoing radiation is taken to be a function of the local temperature. With the requirement for thermal equilibrium, the domain mean temperature is specified as a parameter. The role of condensation is taken into account only as it effectively reduces the static stability. All other external sources and sinks of heat are assumed to balance each other locally, and are thus omitted. The kinematics are th...

11,882 citations

"Evaluation of LES models for flow o..." refers background in this paper

  • ...Ever since Smagorinsky (1963) proposed first model 1 for the SGS stresses, many newer models have been developed....


  • ...2.1 Conventional smagorinsky model Smagorinsky (1963) proposed the first subgrid-scale stress model....


  • ...Ever since Smagorinsky (1963) proposed the first model for the SGS stresses, many newer models have been developed....


  • ... Smagorinsky (1963) proposed the first subgrid-scale stress model....


Proceedings ArticleDOI
Philippe R. Spalart1, S. Allmaras1Institutions (1)
06 Jan 1992-

8,256 citations

Journal ArticleDOI
01 Jul 1991-Physics of Fluids
Abstract: One major drawback of the eddy viscosity subgrid‐scale stress models used in large‐eddy simulations is their inability to represent correctly with a single universal constant different turbulent fields in rotating or sheared flows, near solid walls, or in transitional regimes. In the present work a new eddy viscosity model is presented which alleviates many of these drawbacks. The model coefficient is computed dynamically as the calculation progresses rather than input a priori. The model is based on an algebraic identity between the subgrid‐scale stresses at two different filtered levels and the resolved turbulent stresses. The subgrid‐scale stresses obtained using the proposed model vanish in laminar flow and at a solid boundary, and have the correct asymptotic behavior in the near‐wall region of a turbulent boundary layer. The results of large‐eddy simulations of transitional and turbulent channel flow that use the proposed model are in good agreement with the direct simulation data.

6,329 citations

Journal ArticleDOI
01 Mar 1992-Physics of Fluids
Abstract: The subgrid‐scale closure method developed by Germano et al. is modified by use of a least squares technique to minimize the difference between the closure assumption and the resolved stresses. This modification removes a source of singularity and is believed to improve the method’s applicability.

3,490 citations

Journal ArticleDOI
James W. Deardorff1Institutions (1)
Abstract: The three-dimensional, primitive equations of motion have been integrated numerically in time for the case of turbulent, plane Poiseuille flow at very large Reynolds numbers. A total of 6720 uniform grid intervals were used, with sub-grid scale effects simulated with eddy coefficients proportional to the local velocity deformation. The agreement of calculated statistics against those measured by Laufer ranges from good to marginal. The eddy shapes are examined, and only the u-component, longitudinal eddies are found to be elongated in the downstream direction. However, the lateral v eddies have distinct downstream tilts. The turbulence energy balance is examined, including the separate effects of vertical diffusion of pressure and local kinetic energy.It is concluded that the numerical approach to the problem of turbulence at large Reynolds numbers is already profitable, with increased accuracy to be expected with modest increase of numerical resolution.

1,733 citations

"Evaluation of LES models for flow o..." refers background in this paper

  • ...…study, numerical values of 0·13 and 0·094 have been set forCS andCk respectively to account appropriately for the energy in the resolvable turbulence (Deardorff 1970).1 is the filter width (grid size), and is the characteristic length scale of the largest subgrid-scale eddies and is taken to be…...


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