Numerical simulation of a thermally stratified shear layer using the vortex element method

Ghoniem, Ahmed F.; Heidarinejad, Ghassem; Krishnan, Anantha

doi:10.1016/0021-9991(88)90008-3

Cited by 49 publications

(23 citation statements)

References 24 publications

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“…Thus the solenoidal field can be obtained by the Biot-Savart integral from the vorticity distribution. Following Ghoniem et al, 14 the so-called ''Blob Vortex Method'' originated by Chorin 19 can be generalized to perform simulations of variable-density flows. The numerical procedure aims at tracking a collection of n Lagrangian elements transporting both the local value of the vorticity and the density gradient on a radially symmetric core, characterized by its shape, the ''cut-off'' function f ␦ , and its radius, the ''cut-off'' parameter ␦.…”

Section: Formulation and Numerical Schemesmentioning

confidence: 99%

“…A Lagrangian spatial refinement strategy originated in Ghoniem et al, 14 which inserts or removes elements along isopycnic lines, is adopted and ensures the required overlapping between neighboring blobs, see Leonard. 23 …”

Section: Formulation and Numerical Schemesmentioning

confidence: 99%

“…The problem is normalized by the velocity scale ⌬U/2ϭU 0 , the density 1 of the upper flow, and the length scale . The periodic boundary condition is treated as an exact summation of the velocity field induced by any vortex in the computation domain and its infinite row of images in the other periods ͑Ghoniem et al 14 ͒. The equations are solved with the RK4 scheme and the cut-off function is K4.…”

Section: A the Geometry And Initial Conditionsmentioning

confidence: 99%

“…Both models-the temporal shear layer and the spatially developing mixing layer-are investigated using an extension of the Blob Vortex Method called the Lagrangian Transport Element Method. The method, carrying both the vorticity and the density gradient, has been introduced by Anderson 13 and developed by Ghoniem et al 14 The Lagrangian approach avoids the spatial discretization of the flow gradients and handles advection through the displacement of the elements, limiting the numerical diffusion, see Puckett. 15 This numerical method resolves the scales available from the spatial discretization without much diffusion while considering the smaller scales as a ''substructural phenomena,'' see Soteriou.…”

Section: Introductionmentioning

confidence: 99%

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The baroclinic secondary instability of the two-dimensional shear layer

2000

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The focus of this study is on the numerical investigation of two-dimensional, isovolume, high Reynolds and Froude numbers, variable-density mixing layers. Lagrangian simulations, of both the temporal and the spatial models, are performed. They reveal the breaking-up of the strained vorticity and density-gradient braids, connecting two neighboring primary structures. The secondary instability arises where the vorticity has been intensified by the baroclinic torque. A simplified model of the braid of the variable-density mixing layer, consisting of a strained vorticity and density-gradient filament, is analyzed. It is concluded that the physical mechanism responsible for the secondary instability is the forcing of the vorticity field by the baroclinic torque, itself sensitive to perturbations. This mechanism suggests a rapid route to turbulence for the variable-density mixing layer.

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Section: Formulation and Numerical Schemesmentioning

confidence: 99%

Section: Formulation and Numerical Schemesmentioning

confidence: 99%

Section: A the Geometry And Initial Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The baroclinic secondary instability of the two-dimensional shear layer

2000

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“…The creation of vortex from the temperature is taken into account. Also Ghoniem et al 4,5 studied shear layer and plume rise using the core spreading method for diffusion. The vortex strength is updated by the transport element method in which scalar gradients are used in the transport process.…”

Section: Introductionmentioning

confidence: 99%

Simulation of heat-vortex interaction by the diffusion velocity method

Ogami

1999

ESAIM: Proc.

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A new vortex scheme for simulating flows involving natural convection and interaction of temperature and vorticity is presented. The creation of vorticity from temperature is modeled either by creating a vortex pair from a temperature particle or by changing the strength of vortices according to the vorticity equation. The diffusion velocity method is used for simulating the diffusion of vorticity and temperature. The vortices of negative and positive strength are separately treated in diffusion process to avoid an unreasonably large diffusion velocity. Our results indicates that these techniques successfully simulate creation of vorticity from heat, diffusion and convection of temperature and vorticity, and interaction of them.

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Large eddy simulation (2D) using diffusion–velocity method and vortex‐in‐cell

Milane

2004

Numerical Methods in Fluids

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A large eddy Simulation based on the diffusion‐velocity method and the discrete vortex method is presented. The vorticity‐based and eddy viscosity type subgrid scale model simulating the enstrophy transfer between the large and small scale appears as a convective term in the diffusion‐velocity formulation. The methodology has been tested on a spatially growing mixing layer using the two‐dimensional vortex‐in‐cell method and the Smagorinsky subgrid scale model. The effects on the vorticity contours, momemtum thickness, mean streamwise velocity profiles, root‐mean‐square velocity and vorticity fluctuations and negative cross‐stream correlation are discussed. Comparison is made with experiment and numerical work where diffusion is simulated using random walk. Copyright © 2004 John Wiley & Sons, Ltd.

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Numerical simulation of a thermally stratified shear layer using the vortex element method

Cited by 49 publications

References 24 publications

The baroclinic secondary instability of the two-dimensional shear layer

The baroclinic secondary instability of the two-dimensional shear layer

Simulation of heat-vortex interaction by the diffusion velocity method

Large eddy simulation (2D) using diffusion–velocity method and vortex‐in‐cell

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