The class wallFunctionBlenders is a base class that hosts common entries for various derived wall-function boundary conditions to be used in low- and high-Reynolds number applications. More...

#include <wallFunctionBlenders.H>

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Public Member Functions
	wallFunctionBlenders ()
	Default construct with default coefficients.
	wallFunctionBlenders (const dictionary &dict, const blenderType blender, const scalar n)
	Construct from dictionary and default parameters.
void	writeEntries (Ostream &) const
	Write wall-function blending data as dictionary entries.

Protected Types
enum	blenderType { STEPWISE , MAX , BINOMIAL , EXPONENTIAL , TANH }
	Options for the blending treatment of viscous and inertial sublayers. More...

Protected Attributes
enum blenderType	blender_
	Blending treatment.
scalar	n_
	Binomial blending exponent being used when blenderType is blenderType::BINOMIAL.

Static Protected Attributes
static const Enum< blenderType >	blenderTypeNames
	Names for blenderType.

Detailed Description

The class wallFunctionBlenders is a base class that hosts common entries for various derived wall-function boundary conditions to be used in low- and high-Reynolds number applications.

Reference:

    Default model coefficients (tag:VM):
        Versteeg, H. K., & Malalasekera, W. (2011).
        An introduction to computational fluid dynamics: The finite
        volume method. Harlow: Pearson Education.
        Subsection "3.5.2 k-epsilon model".

    Binomial blending of the viscous and inertial sublayers (tag:ME):
        Menter, F., & Esch, T. (2001).
        Elements of industrial heat transfer prediction.
        In Proceedings of the 16th Brazilian Congress of Mechanical
        Engineering (COBEM), November 2001. vol. 20, p. 117-127.

    Exponential/Max blending of the viscous and inertial sublayers (tag:PH):
        Popovac, M., & Hanjalić, K. (2007).
        Compound wall treatment for RANS computation of complex
        turbulent flows and heat transfer.
        Flow, turbulence and combustion, 78(2), 177-202.
        DOI:10.1007/s10494-006-9067-x

    Tanh blending of the viscous and inertial sublayers (tag:KAS):
        Knopp, T., Alrutz, T., & Schwamborn, D. (2006).
        A grid and flow adaptive wall-function method for RANS
        turbulence modelling.
        Journal of Computational Physics, 220(1), 19-40.
        DOI:10.1016/j.jcp.2006.05.003

Usage

Example of the boundary condition specification:

<patchName>
{
    // Top-level entries
    ...

    // Optional entries
    blending        stepwise;
    n               4.0;

    // Inherited entries
    ...
}

where the entries mean:

Property	Description	Type	Reqd	Deflt
`blending`	Viscous/inertial sublayer blending	word	no	stepwise
`n`	Binomial blending exponent	scalar	no	2.0

Options for the blending entry:

      stepwise    | Stepwise switch (discontinuous)
      max         | Maximum value switch (discontinuous)
      binomial    | Binomial blending (smooth)
      exponential | Exponential blending (smooth)
      tanh        | Tanh blending (smooth)

wherein predictions of a given quantity (e.g. nut) for viscous and inertial sublayers are blended according to the following expressions:

stepwise (default):

$\‍[ \phi = \phi_{log} \qquad if \quad y^+ > y^+_{intersection} \‍]$

$\‍[ \phi = \phi_{vis} \qquad if \quad y^+ <= y^+_{intersection} \‍]$

where

$\phi_{vis}$	=	$\phi$ prediction in viscous sublayer
$\phi_{log}$	=	$\phi$ prediction in inertial sublayer
	=	estimated wall-normal height of cell centre in wall units
$y^+_{intersection}$	=	estimated where sublayers intersect

max (PH:Eq. 27):

$\‍[ \nu_t = max({\nu_t}_{vis}, {\nu_t}_{log}) \‍]$

binomial (ME:Eqs. 15-16):

$\‍[ \phi = ((\phi_{vis})^n + (\phi_{log})^n)^{1/n} \‍]$

where

=

Binomial blending exponent

exponential (PH:Eq. 32):

$\‍[ \phi = \phi_{vis} \exp[-\Gamma] + \phi_{log} \exp[-1/\Gamma] \‍]$

where (PH:Eq. 31)

$\Gamma$	=	Blending expression
$\Gamma$	=

tanh (KAS:Eqs. 33-34):

$\‍[ \phi = \eta \phi_{b1} + (1 - \eta)\phi_{b2} \‍]$

where

$\eta$	=
$\phi_{b1}$	=	$\phi_{vis} + \phi_{log}$
$\phi_{b2}$	=	$(\phi_{vis}^{1.2} + \phi_{log}^1.2)^{1/1.2}$

G predictions for viscous and inertial sublayers are blended in a stepwise manner, and G below $y^+_{intersection}$ (i.e. in the viscous sublayer) is presumed to be zero.

Blending treatments are enabled for the following wall functions:

Source files

Definition at line 249 of file wallFunctionBlenders.H.

Member Enumeration Documentation

◆ blenderType

enum blenderType

protected

Options for the blending treatment of viscous and inertial sublayers.

Enumerator
STEPWISE	"Stepwise switch (discontinuous)"
MAX	"Maximum value switch (discontinuous)"
BINOMIAL	"Binomial blending (smooth)"
EXPONENTIAL	"Exponential blending (smooth)"
TANH	"Tanh blending (smooth)"

Definition at line 258 of file wallFunctionBlenders.H.

Constructor & Destructor Documentation

◆ wallFunctionBlenders() [1/2]

wallFunctionBlenders ( )

Default construct with default coefficients.

Definition at line 44 of file wallFunctionBlenders.C.

References blender_, n_, and STEPWISE.

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◆ wallFunctionBlenders() [2/2]

wallFunctionBlenders	(	const dictionary &	dict,
		const blenderType	blender,
		const scalar	n )

Construct from dictionary and default parameters.

Definition at line 51 of file wallFunctionBlenders.C.

References blender_, blenderTypeNames, dict, n, and n_.

Member Function Documentation

◆ writeEntries()

void writeEntries ( Ostream & os ) const

Write wall-function blending data as dictionary entries.

Definition at line 81 of file wallFunctionBlenders.C.

References BINOMIAL, blender_, blenderTypeNames, n_, and os().

Referenced by epsilonWallFunctionFvPatchScalarField::writeLocalEntries(), nutkWallFunctionFvPatchScalarField::writeLocalEntries(), nutUWallFunctionFvPatchScalarField::writeLocalEntries(), and omegaWallFunctionFvPatchScalarField::writeLocalEntries().

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Member Data Documentation

◆ blenderTypeNames

const Foam::Enum< Foam::wallFunctionBlenders::blenderType > blenderTypeNames

staticprotected

Names for blenderType.

Definition at line 270 of file wallFunctionBlenders.H.

Referenced by wallFunctionBlenders(), and writeEntries().

◆ blender_

enum blenderType blender_

protected

Blending treatment.

Definition at line 278 of file wallFunctionBlenders.H.

Referenced by nutkWallFunctionFvPatchScalarField::calcNut(), nutUWallFunctionFvPatchScalarField::calcNut(), epsilonWallFunctionFvPatchScalarField::calculate(), omegaWallFunctionFvPatchScalarField::calculate(), wallFunctionBlenders(), wallFunctionBlenders(), and writeEntries().

◆ n_

scalar n_

protected

Binomial blending exponent being used when blenderType is blenderType::BINOMIAL.

Definition at line 284 of file wallFunctionBlenders.H.

Referenced by nutkWallFunctionFvPatchScalarField::calcNut(), nutUWallFunctionFvPatchScalarField::calcNut(), epsilonWallFunctionFvPatchScalarField::calculate(), omegaWallFunctionFvPatchScalarField::calculate(), wallFunctionBlenders(), wallFunctionBlenders(), and writeEntries().

The documentation for this class was generated from the following files:

src/TurbulenceModels/turbulenceModels/derivedFvPatchFields/wallFunctions/wallFunction/wallFunctionBlenders/wallFunctionBlenders.H
src/TurbulenceModels/turbulenceModels/derivedFvPatchFields/wallFunctions/wallFunction/wallFunctionBlenders/wallFunctionBlenders.C

Public Member Functions

Protected Types

Protected Attributes

Static Protected Attributes

Detailed Description

Member Enumeration Documentation

◆ blenderType

Constructor & Destructor Documentation

◆ wallFunctionBlenders() [1/2]

◆ wallFunctionBlenders() [2/2]

Member Function Documentation

◆ writeEntries()

Member Data Documentation

◆ blenderTypeNames

◆ blender_

◆ n_