Proper Finite Difference Schemes for Simulations of Incompressible Turbulent Flow in Generalized Curvilinear Coordinates. 2nd Report, Validation of finite difference schemes in Generalized Curvilinear Coordinates.

哲也, 小垣; 敏雄, 小林; 伸行, 谷口

doi:10.1299/kikaib.65.1568

Cited by 2 publications

(3 citation statements)

References 4 publications

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“…Other higher order schemes have been tested [16] and their effect on the relatively fine grids presented in this work has been found to be negligible. A possible explanation is that, since the metric coefficients have been evaluated with a second order scheme, the improvement given by higher order scheme might be balanced by the lower accuracy of the metric coefficients.…”

Section: Codementioning

confidence: 97%

Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels

Merzari

Ninokata

2008

Flow Turbulence Combust

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Eccentric annular pipe flows represent an ideal model for investigating inhomogeneous turbulent shear flows, where conditions of turbulence production and transport vary significantly within the cross-section. Moreover recent works have proven that in geometries characterized by the presence of a narrow gap, large-scale coherent structures are present. The eccentric annular channel represents, in the opinion of the present authors, the prototype of these geometries. The aim of the present work is to verify the capability of a numerical methodology to fully reproduce the main features of the flow field in this geometry, to verify and characterize the presence of large-scale coherent structures, to examine their behavior at different Reynolds numbers and eccentricities and to analyze the anisotropy associated to these structures. The numerical approach is based upon LES, boundary fitted coordinates and a fractional step algorithm. A dynamic Sub Grid Scale (SGS) model suited for this numerical environment has been implemented and tested. An additional interest of this work is therefore in the approach employed itself, considering it as a step into the development of an effective LES methodology for flows in complex channel geometries. Agreement with previous experimental and DNS results has been found good overall for the streamwise velocity, shear stress and the rms of the velocity components. The instantaneous flow field presented large-scale coherent structures in the streamwise direction at low Reynolds numbers, while these are absent or less dominant at higher Reynolds and low eccentricity. After Reynolds averaging is performed over a long integration time the existence of secondary flows in the cross session is proven. Their shape is found to be constant over the Reynolds range surveyed, and dependent on the geometric parameters. The effect of secondary flows on anisotropy is studied over an extensive Reynolds range through invariant analysis. Additional insight on the mechanics of turbulence in this geometry is obtained.

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Section: Codementioning

confidence: 97%

Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels

Merzari

Ninokata

2008

Flow Turbulence Combust

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“…In Morinishi et al (1998), the existing finite difference schemes in regular, staggered and collocated grid systems were analyzed and their conservative properties were also estimated. Based on this study, Kogaki et al (1999) constructed a finite difference code for LES for practical use. After specifying the grid correspondence between physical and computational space, i = i (x 1 , x 2 , x 3 ) and x i = x i ( 1 , 2 , 3 ) for i = 1, 2, 3, and estimating j i = j j /jx i and the Jacobian of the transformation, J = j (x 1 , x 2 , x 3 ) /j( 1 , 2 , 3 ), the governing equations of the LES with the SGS eddy viscosity model are written as…”

Section: Numerical Methods For Lesmentioning

confidence: 99%

“…In the calculations, LES with the G-equation for the flamelet model and the transport equation for the mixture fraction are conducted simultaneously. The governing equations are spatially discretized based on the LES code with a Boundary Fitted Coordinate scheme (Kogaki et al, 1999), which was coded in-house and well parallelized. A second-order central differential scheme was chosen, except for the convection terms of the scalars G and where the QUICK scheme was applied to minimize numerical instability.…”

Section: Les Of Gas-turbine Combustor Flowmentioning

confidence: 99%

Large Eddy simulation for engineering applications

Kobayashi

2006

Fluid Dyn. Res.

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In the field of fluid engineering, controlling turbulent flows remains a crucial problem. This paper presents a basis of numerical methods and turbulence models for the large Eddy simulation. Simulation results include the unsteady analyses of complex flows, such as the vortex dynamics of turbulent jets subject to inlet perturbations and the reacting flow with flame propagation in a gas-turbine combustor flow. Applications employing large Eddy simulation are emerging as one of the most important aspects of the "Frontier Simulation Software for Industrial Science" project for the next generation of fluid dynamic design and development.

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Proper Finite Difference Schemes for Simulations of Incompressible Turbulent Flow in Generalized Curvilinear Coordinates. 2nd Report, Validation of finite difference schemes in Generalized Curvilinear Coordinates.

Cited by 2 publications

References 4 publications

Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels

Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels

Large Eddy simulation for engineering applications

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