Simulation of the flow past a circular cylinder in the supercritical regime by blending RANS and variational-multiscale LES models

Moussaed, Carine; Salvetti, Maria Vittoria; Wornom, Stephen; Koobus, Bruno; Dervieux, Alain

doi:10.1016/j.jfluidstructs.2013.11.006

Cited by 32 publications

(22 citation statements)

References 35 publications

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“…Breuer (2000) performed challenging LES at the subcritical Reynolds number of Re = 1.4 × 10 5 and later, Catalano et al (2003) used LES with wall-modeling at super-critical Reynolds numbers of 5 × 10 5 , 10 6 and 2 × 10 6 . More recently, Moussaed et al (2014) used a blending of a variational multi-scale LES (VMS-LES) with a RANS model for simulating the super-critical regime at Re = 6.5 × 10 5 − 1.25 × 10 6 .…”

Section: Introductionmentioning

confidence: 99%

On the flow past a circular cylinder from critical to super-critical Reynolds numbers: Wake topology and vortex shedding

Rodríguez

Lehmkuhl

Chiva

et al. 2015

International Journal of Heat and Fluid Flow

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The flow past a circular cylinder at critical and supercritical Reynolds number combines flow separation, turbulence transition, reattachment of the flow and further turbulent separation of the boundary layer. The transition to turbulence causes the delaying of the separation point and, an important reduction of the drag force on the cylinder surface. In the present work, large-eddy simulations of the flow past a circular cylinder at Reynolds numbers in the range 2.5 × 10 5 -8.5 × 10 5 are performed. In this range, major changes in the pressure distribution occur, the pressure minimum gets more negative as its location moves towards the cylinder rear, whereas the base pressure increases. These changes are shown to take place first on one side of the cylinder and then on the other side as the drag completes its drop up to a minimum value of ∼0.23, registered at Re = 6.5 × 10 5 in this work. After that, the flow enters in the supercritical regime, with little changes in the wake configuration. Furthermore, these changes in the wake topology as the Reynolds number increases are also shown to be related to the increase in the vortex shedding frequency.

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Section: Introductionmentioning

confidence: 99%

On the flow past a circular cylinder from critical to super-critical Reynolds numbers: Wake topology and vortex shedding

Rodríguez

Lehmkuhl

Chiva

et al. 2015

International Journal of Heat and Fluid Flow

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“…This aims at reducing the excessive damping introduced by eddy-viscosity models on the large scales and at giving reasonable predictions with coarser meshes. References [26,27,25] offer a study of the present hybrid approach's impact on subcritical bluff body flow, in particular in combination with the dynamic method of Germano-Lilly [11,23]. Our motivation in combining RANS with the VMS dynamic formulation is to be able to perform turbulent flow simulations on coarser meshes than with a RANS/LES hybrid model with a comparable accuracy.…”

Section: Methodsologymentioning

confidence: 99%

VMS and OES-Based Hybrid Simulations of Bluff Body Flows

Moussaed

Wornom²,

Koobus

et al. 2016

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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The present article focuses on the improvement of the two components of hybrid RANS/LES models. In the LES component, a Variational Multiscale (VMS) formulation [17] is introduced with the dynamic control of Germano et al, [11]. In the RANS component, an Organised Eddy Simulation (OES) model is used, [4,39]. The impact of these modifications on several critical flows past bluff bodies is analysed. These are the flow past cylinder at Re = 140, 000 entering the critical regime because of blockage ratio confinement, a flow past a cylinder at Re = 1, 000, 000, as well as the flow past a tandem cylinder at Re = 166, 000.Key words: hybrid turbulence models, RANS, VMS-LES, OES, DDES, bluff body flows.VMS-and OES-based hybrid simulations of bluff body flows and the existence of asymmetric forces on the cylinder surface (Bearman, 1965;Schewe, 1983). The passage to the critical and supercritical regime highly interests the aeronautics design and from a fundamental research point of view, the reasons of vortex shedding disappearance in a specific supercritical Reynolds number range. The numerical simulation of the drag crisis and of the supercritical regime remain important CFD challenges. The supercritical regime offers the possibility of the boundary layer treatment as fully turbulent, which is a simpler situation in respect for turbulence modelling issues than the transitional regime corresponding to the drag crisis. In this context, LES approaches and advanced URANS and hybrid RANS-LES methods can be adapted in order to capture the boundary layer nature and the transition location. LES methods need a quite high number of degrees of freedom (of order 100-500 Million for the single cylinder's problem, Rolfo-Revell et al, (2013) [34], Rodriguez et al, 2013 [18]), whereas hybrid methods are generally more economic as seen in the collected articles of the 4th Hybrid RANS-LES methods symposium (Girimaji et al, 2015 [1]). The objective of the present article is to offer reliable hybrid methods needing relatively economic grids.

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“…The parallelism relies on mesh partitioning and MPI. A description of this tool, which solves with a mixed element/volume method on unstructured meshes the compressible Euler and Navier-Stokes equations possibly equipped with a turbulence model, can be found in [20] and [21]. When computing hybrid RANS-LES flows, an important part of the mesh is dedicated to the boundary layer and involved possibly very small cells.…”

Section: Applicationsmentioning

confidence: 99%

A Volume-Agglomeration Multirate Time Advancing Approach

Itam¹,

Wornom²,

Koobus³

et al. 2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Abstract. A frequent configuration in computational fluid mechanics combines an explicit time advancing scheme for accuracy purposes and a computational grid with a very small portion of much smaller elements than in the remaining mesh. Examples of such situations are the traveling of a discontinuity followed by a moving mesh, and the large eddy simulation of high Reynolds number flows around bluff bodies where together very thin boundary layers and vortices of much more important size need to be captured. For such configurations, explicit time advancing schemes with global time stepping are very costly. In order to overcome this problem, the multirate time stepping approach represents an interesting improvement. The objective of such schemes, which allow to use different time steps in the computational domain, is to avoid penalizing the computational cost of the time advancement of unsteady solutions which can become large due to the use of small global time steps imposed by the smallest elements such as those constituting the boundary layers. In the present work, a new multirate scheme based on control volume agglomeration is proposed for the solution of the compressible Navier-Stokes equations possibly equipped with turbulence models. The method relies on a prediction step where large time steps are performed with an evaluation of the fluxes on macro-cells for the smaller elements for stability purpose, and on a correction step in which small time steps are employed only for the smaller elements. The efficiency of the proposed method is evaluated on several benchmarks flows: the problem of a moving contact discontinuity (inviscid flow), the computation with hybrid turbulence model of flows around bluff bodies like a tandem cylinders at Reynolds number 1.66 × 10 5 , a circular cylinder at Reynolds number 8.4 × 10 6 , and a flow around a space probe model at Reynolds number 1 × 10 6 .4703

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Simulation of the flow past a circular cylinder in the supercritical regime by blending RANS and variational-multiscale LES models

Cited by 32 publications

References 35 publications

On the flow past a circular cylinder from critical to super-critical Reynolds numbers: Wake topology and vortex shedding

On the flow past a circular cylinder from critical to super-critical Reynolds numbers: Wake topology and vortex shedding

VMS and OES-Based Hybrid Simulations of Bluff Body Flows

A Volume-Agglomeration Multirate Time Advancing Approach

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