scholarly journals Interface boundary conditions in near-wall turbulence modeling

2012 ◽  
Vol 68 ◽  
pp. 186-191 ◽  
Author(s):  
S.V. Utyuzhnikov
Keyword(s):  
Boundary Conditions ◽  
Turbulence Modeling ◽  
Wall Turbulence ◽  
Interface Boundary ◽  
Interface Boundary Conditions ◽  
Near Wall Turbulence ◽  
Near Wall

Near-Wall Turbulence Modeling Without Wall Distance

2004 ◽  
Author(s):  
M. M. Rahman ◽  
T. Siikonen
Keyword(s):  
Turbulence Modeling ◽  
Adverse Pressure Gradient ◽  
Wall Turbulence ◽  
Gradient Flows ◽  
Wall Function ◽  
Cross Diffusion ◽  
Near Wall Turbulence ◽  
Good Agreement ◽  
Flow Separation And Reattachment ◽  
Near Wall

A low-Reynolds number k-ε model is proposed in which the anisotropic production in near-wall regions is accounted for substantially by modifying the model constants Cε(1,2) and adding cross-diffusion terms in the ε equation. Hence, it reduces the kinetic energy and length scale magnitudes to improve prediction of adverse pressure gradient flows, involving flow separation and reattachment. Unlike the conventional k-ε model, it requires no wall function/distance parameter that bridges the near-wall integration. The model coefficients/functions depend nonlinearly on both the strain-rate and vorticity invariants. The model is validated against a few flow cases, yielding predictions in good agreement with the direct numerical simulation (DNS) and experimental data.

On unified boundary conditions for improved predictions of near-wall turbulence

2010 ◽  
Vol 656 ◽  
pp. 530-539 ◽  
Author(s):  
S. JAKIRLIĆ ◽  
J. JOVANOVIĆ
Keyword(s):  
Boundary Conditions ◽  
Viscous Sublayer ◽  
Wall Turbulence ◽  
Wall Region ◽  
Homogeneous Part ◽  
Wall Distance ◽  
Wall Boundary Conditions ◽  
Close Proximity ◽  
Near Wall Turbulence ◽  
Near Wall

A novel formulation of the wall boundary conditions relying on the asymptotic behaviour of the Taylor microscale λ and its relationship to the homogeneous part of the viscous dissipation rate of the kinetic energy of turbulence εh=5νq2/λ2, applicable to near-wall turbulence, is examined. The linear dependence of λ on the wall distance in close proximity to the solid surface enables the wall-closest grid node to be positioned immediately below the edge of the viscous sublayer, leading to a substantial coarsening of the grid resolution. This approach provides bridging of a major portion of the viscous sublayer, higher grid flexibility and weaker sensitivity against the grid non-uniformities in the near-wall region. The performance of the proposed formulation was checked against available direct numerical simulation databases of complex wall-bounded flows featured by swirl and separation.

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