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Class
Foam::resolutionIndexModels::CelikNuIndex
Description
Computes a single-mesh resolution index according to Celik et al.'s index
using effective viscosity, which is used as a LES/DES quality/post
verification metric that does not require any experimental or DNS data.
\f[
\Gamma_{Celik,\nu}(\mathbf{x}, t) =
\frac{1}{1 + \alpha_\nu \left(\frac{\nu_{eff}}{\nu}\right)^n}
\f]
with
\f[
\nu_{eff} = \nu_{num} + \nu_{sgs} + \nu
\f]
\f[
\nu_{num} = {sgn}(k_{num}) C_\nu \Delta \sqrt{k_{num}}
\f]
\f[
k_{num} = C_n \left(\frac{h}{\Delta}\right)^2 k_{sgs}
\f]
where
\vartable
\Gamma_{Celik,\nu}(\mathbf{x}, t) | Celik et al.'s index [-]
\alpha_\nu | Empirical constant [-]
\nu_{eff} | Effective eddy viscosity [m^2/s]
\nu_{num} | Numerical eddy viscosity [m^2/s]
\nu_{sgs} | Subgrid-scale eddy viscosity [m^2/s]
\nu | Kinematic viscosity of fluid [m^2/s]
n | Empirical exponent [-]
k_{num} | Numerical turbulent kinetic energy [m^2/s^2]
C_\nu | Empirical constant [-]
\Delta | Filter length scale [m]
C_n | Empirical constant [-]
h | Characteristic length scale with \f$h = V^{1/3} \f$ [m]
V | Cell volume [m^3]
k_{sgs} | Subgrid-scale turbulent kinetic energy [m^2/s^2]
\endvartable
Criterion for acceptable-quality resolution:
\f[
\Gamma_{Celik,\nu}(\mathbf{x}) \geq 0.8
\f]
Required fields:
\verbatim
k | Subgrid scale turbulent kinetic energy [m^2/s^2]
delta | Filter length [m]
nu | Kinematic viscosity [m^2/s]
nut | Subgrid-scale eddy viscosity [m^2/s]
\endverbatim
References:
\verbatim
Governing equations (tag:CCY):
Celik, I. B., Cehreli Z. N., Yavuz I. (2005).
Index of resolution quality for large eddy simulations.
Journal of Fluids Engineering. 127:949–958.
DOI:10.1115/1.1990201
Governing equations (tag:CKJ):
Celik, I., Klein, M., & Janicka, J. (2009).
Assessment measures for engineering LES applications.
Journal of fluids engineering, 131(3).
DOI:10.1115/1.3059703
\endverbatim
Usage
Minimal example by using \c system/controlDict.functions:
\verbatim
resolutionIndex1
{
// Inherited entries
...
model CelikNuIndex;
// Optional entries
alphaNu ;
n ;
Cnu ;
Cn ;
k ;
delta ;
nu ;
nut ;
}
\endverbatim
where the entries mean:
\table
Property | Description | Type | Reqd | Deflt
model | Model name: CelikNuIndex | word | yes | -
alphaNu | Empirical constant | scalar | no | 0.05
n | Empirical exponent | scalar | no | 0.53
Cnu | Empirical constant | scalar | no | 0.1
Cn | Empirical constant | scalar | no | 1.0
k | Name of subgrid-scale turbulent kinetic energy field | word | no | k
delta | Name of filter field | word | no | delta
nu | Name of kinematic viscosity field | word | no | nu
nut | Name of subgrid-scale eddy viscosity field | word | no | nut
\endtable
SourceFiles
CelikNuIndex.C
\*---------------------------------------------------------------------------*/
#ifndef Foam_resolutionIndexModels_CelikNuIndex_H
#define Foam_resolutionIndexModels_CelikNuIndex_H
#include "resolutionIndexModel.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
namespace resolutionIndexModels
{
/*---------------------------------------------------------------------------*\
Class CelikNuIndex Declaration
\*---------------------------------------------------------------------------*/
class CelikNuIndex
:
public resolutionIndexModel
{
// Private Data
//- Empirical constant
scalar alphaNu_;
//- Empirical exponent
scalar n_;
//- Empirical constant
scalar Cnu_;
//- Empirical constant
scalar Cn_;
//- Name of subgrid-scale turbulent kinetic energy field
word kName_;
//- Name of filter field
word deltaName_;
//- Name of kinematic viscosity field
word nuName_;
//- Name of subgrid-scale eddy viscosity field
word nutName_;
// Private Member Functions
//- Return numerical eddy viscosity field
tmp nuNum() const;
//- Return numerical turbulent kinetic energy field
tmp kNum() const;
public:
//- Runtime type information
TypeName("CelikNuIndex");
// Constructors
//- Construct from components
CelikNuIndex
(
const word& name,
const fvMesh& mesh,
const dictionary& dict
);
//- No copy construct
CelikNuIndex(const CelikNuIndex&) = delete;
//- No copy assignment
void operator=(const CelikNuIndex&) = delete;
// Destructor
virtual ~CelikNuIndex() = default;
// Member Functions
//- Read top-level dictionary
virtual bool read(const dictionary& dict);
//- Calculate the result field
virtual bool execute();
//- Write the result field
virtual bool write();
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace resolutionIndexModels
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //