Commit 8a188a1f authored by Kutalmis Bercin's avatar Kutalmis Bercin Committed by Andrew Heather
Browse files

ENH-DOC: fix inconsistent Cmu lookup (fixes #647)

parent d0d3670d
......@@ -48,8 +48,9 @@ turbulentMixingLengthDissipationRateInletFvPatchScalarField
)
:
inletOutletFvPatchScalarField(p, iF),
kName_("k"),
mixingLength_(0.0),
kName_("k")
Cmu_(0.0)
{
this->refValue() = 0.0;
this->refGrad() = 0.0;
......@@ -67,8 +68,9 @@ turbulentMixingLengthDissipationRateInletFvPatchScalarField
)
:
inletOutletFvPatchScalarField(ptf, p, iF, mapper),
kName_(ptf.kName_),
mixingLength_(ptf.mixingLength_),
kName_(ptf.kName_)
Cmu_(ptf.Cmu_)
{}
......@@ -81,8 +83,12 @@ turbulentMixingLengthDissipationRateInletFvPatchScalarField
)
:
inletOutletFvPatchScalarField(p, iF),
mixingLength_(dict.get<scalar>("mixingLength")),
kName_(dict.getOrDefault<word>("k", "k"))
kName_(dict.getOrDefault<word>("k", "k")),
mixingLength_
(
dict.getCheck<scalar>("mixingLength", scalarMinMax::ge(SMALL))
),
Cmu_(dict.getCheckOrDefault<scalar>("Cmu", 0.09, scalarMinMax::ge(SMALL)))
{
this->phiName_ = dict.getOrDefault<word>("phi", "phi");
......@@ -101,8 +107,9 @@ turbulentMixingLengthDissipationRateInletFvPatchScalarField
)
:
inletOutletFvPatchScalarField(ptf),
kName_(ptf.kName_),
mixingLength_(ptf.mixingLength_),
kName_(ptf.kName_)
Cmu_(ptf.Cmu_)
{}
......@@ -114,8 +121,9 @@ turbulentMixingLengthDissipationRateInletFvPatchScalarField
)
:
inletOutletFvPatchScalarField(ptf, iF),
kName_(ptf.kName_),
mixingLength_(ptf.mixingLength_),
kName_(ptf.kName_)
Cmu_(ptf.Cmu_)
{}
......@@ -138,10 +146,9 @@ void turbulentMixingLengthDissipationRateInletFvPatchScalarField::updateCoeffs()
)
);
const scalar Cmu =
turbModel.coeffDict().getOrDefault<scalar>("Cmu", 0.09);
Cmu_ = turbModel.coeffDict().getOrDefault<scalar>("Cmu", Cmu_);
const scalar Cmu75 = pow(Cmu, 0.75);
const scalar Cmu75 = pow(Cmu_, 0.75);
const fvPatchScalarField& kp =
patch().lookupPatchField<volScalarField, scalar>(kName_);
......@@ -149,7 +156,7 @@ void turbulentMixingLengthDissipationRateInletFvPatchScalarField::updateCoeffs()
const fvsPatchScalarField& phip =
patch().lookupPatchField<surfaceScalarField, scalar>(this->phiName_);
this->refValue() = Cmu75*kp*sqrt(kp)/mixingLength_;
this->refValue() = (Cmu75/mixingLength_)*pow(kp, 1.5);
this->valueFraction() = 1.0 - pos0(phip);
inletOutletFvPatchScalarField::updateCoeffs();
......
......@@ -6,6 +6,7 @@
\\/ M anipulation |
-------------------------------------------------------------------------------
Copyright (C) 2011-2016 OpenFOAM Foundation
Copyright (C) 2020 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
......@@ -30,43 +31,63 @@ Group
grpRASBoundaryConditions grpInletBoundaryConditions
Description
This boundary condition provides a turbulence dissipation, \f$\epsilon\f$
(epsilon) inlet condition based on a specified mixing length. The patch
values are calculated using:
This boundary condition provides an inlet condition for turbulent kinetic
energy dissipation rate, i.e. \c epsilon, based on a specified mixing
length. The patch values are calculated using:
\f[
\epsilon_p = \frac{C_{\mu}^{0.75} k^{1.5}}{L}
\f]
where
\vartable
\epsilon_p | patch epsilon values
C_{\mu} | Model coefficient, set to 0.09
k | turbulence kinetic energy
L | length scale
\epsilon_p | Patch epsilon values [m2/s3]
C_\mu | Empirical model constant retrived from turbulence model
k | Turbulent kinetic energy [m2/s2]
L | Mixing length scale [m]
\endvartable
Usage
\table
Property | Description | Required | Default value
mixingLength | Length scale [m] | yes |
phi | flux field name | no | phi
k | turbulence kinetic energy field name | no | k
\endtable
Example of the boundary condition specification:
\verbatim
<patchName>
{
// Mandatory entries (unmodifiable)
type turbulentMixingLengthDissipationRateInlet;
// Mandatory entries (runtime modifiable)
mixingLength 0.005;
value uniform 200; // placeholder
// Optional entries (runtime modifiable)
Cmu 0.09;
k k;
phi phi;
// Placeholder
value uniform 200;
}
\endverbatim
where the entries mean:
\table
Property | Description | Type | Req'd | Dflt
mixingLength | Mixing length scale [m] | scalar | yes | -
Cmu | Empirical model constant | scalar | no | 0.09
phi | Name of flux field | word | no | phi
k | Name of turbulent kinetic energy field | word | no | k
\endtable
Note
In the event of reverse flow, a zero-gradient condition is applied
- The boundary condition is derived from \c inletOutlet condition.
Therefore, in the event of reverse flow, a zero-gradient condition
is applied.
- The order of precedence to input the empirical model constant \c Cmu is:
turbulence model, boundary condition dictionary, and default value=0.09.
- The empirical model constant \c Cmu is not a spatiotemporal variant field.
Therefore, the use of the boundary condition may not be fully consistent
with the turbulence models where \c Cmu is a variant field, such as
\c realizableKE closure model in this respect. Nevertheless, workflow
observations suggest that the matter poses no importance.
See also
Foam::inletOutletFvPatchField
......@@ -94,14 +115,17 @@ class turbulentMixingLengthDissipationRateInletFvPatchScalarField
:
public inletOutletFvPatchScalarField
{
// Private data
//- Turbulent length scale
scalar mixingLength_;
// Private Data
//- Name of the turbulent kinetic energy field
word kName_;
//- Mixing length scale
scalar mixingLength_;
//- Empirical model constant
scalar Cmu_;
public:
......@@ -127,8 +151,8 @@ public:
);
//- Construct by mapping given
// turbulentMixingLengthDissipationRateInletFvPatchScalarField
// onto a new patch
//- turbulentMixingLengthDissipationRateInletFvPatchScalarField
//- onto a new patch
turbulentMixingLengthDissipationRateInletFvPatchScalarField
(
const turbulentMixingLengthDissipationRateInletFvPatchScalarField&,
......@@ -179,7 +203,7 @@ public:
}
// Member functions
// Member Functions
//- Update the coefficients associated with the patch field
virtual void updateCoeffs();
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment