On the elimination of wall‐topography parameters from second‐moment closure

Abstract A multiblock Favre-Averaged Navier-Stokes (FANS) method has been developed in conjunction with a chimera domain decomposition technique for investigation of flat surface, discrete-hole film cooling performance. The finite-analytic method solves the FANS equations in conjunction with a near-wall second-order Reynolds stress (second-moment) closure model and a two-layer k-ε model. Comparisons of flow fields and turbulence quantities with experimental data clearly demonstrate the capability of the near-wall second-moment closure model for accurate resolution of the complex flow interaction bewteen the coolant jet and the mainstream. The near-wall second-moment anisotropic model provides better agreement in adiabatic film effectiveness prediction than the two-layer k-ε model.

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Low-Reynolds-number second-moment closure without wall-reflection redistribution terms

International Journal of Heat and Fluid Flow ◽

10.1016/s0142-727x(98)10012-7 ◽

1998 ◽

Vol 19 (5) ◽

pp. 549-555 ◽

Cited By ~ 31

Author(s):

Nobuyuki Shima

Keyword(s):

Reynolds Number ◽

Low Reynolds Number ◽

Moment Closure ◽

Second Moment ◽

Second Moment Closure ◽

Low Reynolds

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A Comparison of Algebraic and Differential Second-Moment Closures for Axisymmetric Turbulent Shear Flows With and Without Swirl

Journal of Fluids Engineering ◽

10.1115/1.3243537 ◽

1988 ◽

Vol 110 (2) ◽

pp. 216-221 ◽

Cited By ~ 54

Author(s):

S. Fu ◽

P. G. Huang ◽

B. E. Launder ◽

M. A. Leschziner

Keyword(s):

Shear Flows ◽

Turbulent Jets ◽

Moment Closure ◽

Turbulent Shear ◽

Turbulence Energy ◽

Second Moment ◽

Second Moment Closure ◽

Transport Effects ◽

Related Stress ◽

Comparison Of The Results

Computations are reported for three axisymmetric turbulent jets, two of which are swirling and one containing swirl-induced recirculation, obtained with two models of turbulence: a differential second-moment (DSM) closure and an algebraic derivative thereof (ASM). The models are identical in respect of all turbulent processes except that, in the ASM scheme, stress transport is represented algebraically in terms of the transport of turbulence energy. The comparison of the results thus provides a direct test of how well the model of stress transport adopted in ASM schemes simulates that of the full second-moment closure. The comparison indicates that the ASM hypothesis seriously misrepresents the diffusive transport of the shear stress in nonswirling axisymmetric flows, while in the presence of swirl the defects extend to all stress components and are aggravated by a failure to account for influential (additive) swirl-related stress-transport terms in the algebraic modelling process. The principal conclusion thus drawn is that in free shear flows where transport effects are significant, it is advisable to adopt a full second-moment closure if turbulence modelling needs to proceed beyond the eddy-viscosity level.

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