ENH: heatTransferCoeff: add optional Nusselt number functionality

DOC: heatTransferCoeff models: complete remaining header docs
  STYLE: heatTransferCoeff models: use auto specifier when appropriate

  Optionally, the Nusselt number (i.e. the ratio of convective to conductive
  heat transfer at a boundary in a fluid) can be output:

  ```math
      Nu = \frac{h L}{\kappa}
  ```

  where
  ```
    Nu | Nusselt number
    h  | Convective heat transfer coefficient of the flow
    L  | Characteristic length that defines the scale of the physical system
    \kappa | Thermal conductivity of the fluid
  ```

src/functionObjects/field/heatTransferCoeff/heatTransferCoeff.C

@@ -45,10 +45,12 @@ namespace functionObjects
 
 bool Foam::functionObjects::heatTransferCoeff::calc()
 {
-    volScalarField& htc = mesh_.lookupObjectRef<volScalarField>(resultName_);
+    auto& htc = mesh_.lookupObjectRef<volScalarField>(resultName_);
 
     htcModelPtr_->calc(htc, htcModelPtr_->q());
 
+    htc *= L_/kappa_;
+
     return true;
 }
 
@@ -63,13 +65,15 @@ Foam::functionObjects::heatTransferCoeff::heatTransferCoeff
 )
 :
     fieldExpression(name, runTime, dict),
+    L_(1),
+    kappa_(1),
     htcModelPtr_(nullptr)
 {
     read(dict);
 
     setResultName(typeName, name + ":htc:" + htcModelPtr_->type());
 
-    volScalarField* heatTransferCoeffPtr =
+    auto* heatTransferCoeffPtr =
         new volScalarField
         (
             IOobject
@@ -92,8 +96,14 @@ Foam::functionObjects::heatTransferCoeff::heatTransferCoeff
 
 bool Foam::functionObjects::heatTransferCoeff::read(const dictionary& dict)
 {
-    if (fieldExpression::read(dict))
+    if (!fieldExpression::read(dict))
     {
+        return false;
+    }
+
+    L_ = dict.getCheckOrDefault<scalar>("L", 1, scalarMinMax::ge(0));
+    kappa_ =
+        dict.getCheckOrDefault<scalar>("kappa", 1, scalarMinMax::ge(SMALL));
     htcModelPtr_ = heatTransferCoeffModel::New(dict, mesh_, fieldName_);
 
     htcModelPtr_->read(dict);
@@ -101,8 +111,5 @@ bool Foam::functionObjects::heatTransferCoeff::read(const dictionary& dict)
     return true;
 }
 
-    return false;
-}
-
 
 // ************************************************************************* //

src/functionObjects/field/heatTransferCoeff/heatTransferCoeff.H

@@ -30,11 +30,23 @@ Group
     grpFieldFunctionObjects
 
 Description
-    Computes the heat transfer coefficient as a \c volScalarField
+    Computes the heat transfer coefficient [W/(m2 K)]
-    for a set of patches.
+    as a \c volScalarField for a given set of patches.
 
-    The field is stored on the mesh database so that it can be retrieved and
+    Optionally, the Nusselt number (i.e. the ratio of convective
-    used for other applications.
+    to conductive heat transfer at a boundary in a fluid) can be output:
+
+    \f[
+        Nu = \frac{h L}{\kappa}
+    \f]
+
+    where
+    \vartable
+      Nu | Nusselt number
+      h  | Convective heat transfer coefficient of the flow
+      L  | Characteristic length that defines the scale of the physical system
+      \kappa | Thermal conductivity of the fluid
+    \endvartable
 
     Operands:
     \table
@@ -53,79 +65,44 @@ Usage
         type        heatTransferCoeff;
         libs        (fieldFunctionObjects);
 
-        field       T;
+        // Mandatory (inherited) entries (runtime modifiable)
-        patches     ("walls.*");
+        field       <field>;
+        patches     (<patch1> <patch2> ... <patchN>);
+        htcModel    <htcModel>;
 
-        htcModel    ReynoldsAnalogy;
+        // Optional entries (runtime modifable)
-        UInf        (20 0 0);
+        qr          <qrName>;
-        Cp          CpInf;
+        L           1.0;
-        CpInf       1000;
+        kappa       1.0;
-        rho         rhoInf;
+
-        rhoInf      1.2;
+        // Conditional mandatory and optional
+        // entries based on selected <htcModel> (runtime modifiable)
+        ...
+
+        // Optional (inherited) entries
+        ...
     }
     \endverbatim
 
-    Example usage for mode \c ReynoldsAnalogy for incompressible case:
+    where the entries mean:
-    \verbatim
+    \table
-    heatTransferCoeff1
+      Property    | Description                        | Type | Reqd | Dflt
-    {
+      type        | Type name: heatTransferCoeff       | word | yes  | -
-        // Mandatory entries (unmodifiable)
+      libs        | Library name: fieldFunctionObjects | word | yes  | -
-        type        heatTransferCoeff;
+      field       | Name of the operand field          | word | yes  | -
-        libs        (fieldFunctionObjects);
+      patches     | Names of operand patches        | wordRes | yes  | -
+      htcModel    | Heat transfer coefficient model <!--
+                -->                        - see below | word | yes  | -
+      qr          | Name of radiative heat flux        | word | no   | qr
+      L           | Characteristic length that defines <!--
+                --> the scale of the physical system | scalar | no   | 1
+      kappa       | Thermal conductivity of fluid    | scalar | no   | 1
+    \endtable
 
-        field       T;
+    The inherited entries are elaborated in:
-        patches     ("walls.*");
+      - \link functionObject.H \endlink
-
+      - \link fieldExpression.H \endlink
-        htcModel    ReynoldsAnalogy;
+      - \link heatTransferCoeffModel.H \endlink
-        UInf        (20 0 0);
-        Cp          CpInf;
-        CpInf       1000;
-        rho         rhoInf;
-        rhoInf      1.2;
-    }
-    \endverbatim
-
-    Example usage for mode \c ReynoldsAnalogy for compressible case:
-    \verbatim
-    htc
-    {
-        type        heatTransferCoeff;
-        libs        (fieldFunctionObjects);
-
-        field       T;
-        patches     ("walls.*");
-
-        htcModel    ReynoldsAnalogy;
-        UInf        (20 0 0);
-    }
-    \endverbatim
-
-    Example usage for mode \c localReferenceTemperature for compressible case:
-    \verbatim
-    htc
-    {
-        type        heatTransferCoeff;
-        libs        (fieldFunctionObjects);
-
-        field       T;
-        patches     ("walls.*");
-        htcModel    localReferenceTemperature;
-    }
-    \endverbatim
-
-    Example usage for mode \c fixedReferenceTemperature for compressible case:
-    \verbatim
-    htc
-    {
-        type        heatTransferCoeff;
-        libs        (fieldFunctionObjects);
-
-        field       T;
-        patches     ("walls.*");
-        htcModel    fixedReferenceTemperature;
-        TRef        300;
-    }
-    \endverbatim
 
     Options for the \c htcModel entry:
     \verbatim
@@ -134,10 +111,6 @@ Usage
       fixedReferenceTemperature | Specified reference temperature
     \endverbatim
 
-    The inherited entries are elaborated in:
-     - \link functionObject.H \endlink
-     - \link fieldExpression.H \endlink
-
     Usage by the \c postProcess utility is not available.
 
 See also
@@ -145,6 +118,7 @@ See also
   - Foam::functionObjects::fieldExpression
   - Foam::heatTransferCoeffModels::fixedReferenceTemperature
   - Foam::heatTransferCoeffModels::localReferenceTemperature
+  - Foam::heatTransferCoeffModels::ReynoldsAnalogy
   - ExtendedCodeGuide::functionObjects::field::heatTransferCoeff
 
 SourceFiles
@@ -178,6 +152,12 @@ class heatTransferCoeff
 {
     // Private Data
 
+        //- Characteristic length that defines the scale of the physical system
+        scalar L_;
+
+        //- Thermal conductivity of the fluid
+        scalar kappa_;
+
         //- Heat transfer coefficient model
         autoPtr<heatTransferCoeffModel> htcModelPtr_;
 
@@ -197,6 +177,9 @@ public:
 
     // Constructors
 
+        //- No default construct
+        heatTransferCoeff() = delete;
+
         //- Construct for given objectRegistry and dictionary.
         //  Allow the possibility to load fields from files
         heatTransferCoeff

src/functionObjects/field/heatTransferCoeff/heatTransferCoeffModels/ReynoldsAnalogy/ReynoldsAnalogy.C

@@ -60,8 +60,7 @@ Foam::heatTransferCoeffModels::ReynoldsAnalogy::rho(const label patchi) const
     }
     else if (mesh_.foundObject<volScalarField>(rhoName_, false))
     {
-        const volScalarField& rho =
+        const auto& rho = mesh_.lookupObject<volScalarField>(rhoName_);
-            mesh_.lookupObject<volScalarField>(rhoName_);
         return rho.boundaryField()[patchi];
     }
 
@@ -83,7 +82,7 @@ Foam::heatTransferCoeffModels::ReynoldsAnalogy::Cp(const label patchi) const
     }
     else if (mesh_.foundObject<fluidThermo>(fluidThermo::dictName))
     {
-        const fluidThermo& thermo =
+        const auto& thermo =
             mesh_.lookupObject<fluidThermo>(fluidThermo::dictName);
 
         const scalarField& pp = thermo.p().boundaryField()[patchi];
@@ -108,7 +107,7 @@ Foam::heatTransferCoeffModels::ReynoldsAnalogy::devReff() const
 
     if (mesh_.foundObject<cmpTurbModel>(cmpTurbModel::propertiesName))
     {
-        const cmpTurbModel& turb =
+        const auto& turb =
             mesh_.lookupObject<cmpTurbModel>(cmpTurbModel::propertiesName);
 
         return turb.devRhoReff()/turb.rho();
@@ -122,30 +121,30 @@ Foam::heatTransferCoeffModels::ReynoldsAnalogy::devReff() const
     }
     else if (mesh_.foundObject<fluidThermo>(fluidThermo::dictName))
     {
-        const fluidThermo& thermo =
+        const auto& thermo =
             mesh_.lookupObject<fluidThermo>(fluidThermo::dictName);
 
-        const volVectorField& U = mesh_.lookupObject<volVectorField>(UName_);
+        const auto& U = mesh_.lookupObject<volVectorField>(UName_);
 
         return -thermo.nu()*dev(twoSymm(fvc::grad(U)));
     }
     else if (mesh_.foundObject<transportModel>("transportProperties"))
     {
-        const transportModel& laminarT =
+        const auto& laminarT =
             mesh_.lookupObject<transportModel>("transportProperties");
 
-        const volVectorField& U = mesh_.lookupObject<volVectorField>(UName_);
+        const auto& U = mesh_.lookupObject<volVectorField>(UName_);
 
         return -laminarT.nu()*dev(twoSymm(fvc::grad(U)));
     }
     else if (mesh_.foundObject<dictionary>("transportProperties"))
     {
-        const dictionary& transportProperties =
+        const auto& transportProperties =
             mesh_.lookupObject<dictionary>("transportProperties");
 
-        dimensionedScalar nu("nu", dimViscosity, transportProperties);
+        const dimensionedScalar nu("nu", dimViscosity, transportProperties);
 
-        const volVectorField& U = mesh_.lookupObject<volVectorField>(UName_);
+        const auto& U = mesh_.lookupObject<volVectorField>(UName_);
 
         return -nu*dev(twoSymm(fvc::grad(U)));
     }
@@ -161,7 +160,7 @@ Foam::heatTransferCoeffModels::ReynoldsAnalogy::devReff() const
 Foam::tmp<Foam::FieldField<Foam::Field, Foam::scalar>>
 Foam::heatTransferCoeffModels::ReynoldsAnalogy::Cf() const
 {
-    const volVectorField& U = mesh_.lookupObject<volVectorField>(UName_);
+    const auto& U = mesh_.lookupObject<volVectorField>(UName_);
     const volVectorField::Boundary& Ubf = U.boundaryField();
 
     auto tCf = tmp<FieldField<Field, scalar>>::New(Ubf.size());
@@ -205,9 +204,9 @@ Foam::heatTransferCoeffModels::ReynoldsAnalogy::ReynoldsAnalogy
     UName_("U"),
     URef_(Zero),
     rhoName_("rho"),
-    rhoRef_(0.0),
+    rhoRef_(0),
     CpName_("Cp"),
-    CpRef_(0.0)
+    CpRef_(0)
 {
     read(dict);
 }

src/functionObjects/field/heatTransferCoeff/heatTransferCoeffModels/ReynoldsAnalogy/ReynoldsAnalogy.H

@@ -27,10 +27,11 @@ Class
     Foam::heatTransferCoeffModels::ReynoldsAnalogy
 
 Description
-    Heat transfer coefficient calculation based on Reynolds Analogy
+    Heat transfer coefficient calculation based on Reynolds Analogy,
+    which is used to relate turbulent momentum and heat transfer.
 
-    The heat transfer coefficient is derived from the skin friction
+    The heat transfer coefficient is derived
-    coefficient:
+    from the skin friction coefficient:
 
     \f[
         C_f = \frac{\tau_w}{0.5 \rho_\infty |U|^2}
@@ -39,42 +40,66 @@ Description
     as:
 
     \f[
-        h = 0.5 \rho_\infty C_{p,\infty} |U_{\infty}| C_f
+        h = 0.5 \rho_\infty c_{p,\infty} |U_{\infty}| C_f
     \f]
 
+    where
+    \vartable
+      h       | Convective heat transfer coefficient of the flow
+      \rho_\infty  | Reference fluid density
+      c_{p,\infty} | Reference specific heat capacity at constant pressure
+      U_{\infty}   | Reference velocity
+      C_f          | Skin friction coefficient
+      \tau_w       | Wall shear stress
+    \endvartable
+
 Usage
-    Example of function object specification:
+    Minimal example by using \c system/controlDict.functions:
     \verbatim
-        type            heatTransferCoeff;
+    heatTransferCoeff1
-        libs            (fieldFunctionObjects);
+    {
+        // Mandatory and other optional entries
         ...
         htcModel        ReynoldsAnalogy;
-        UInf            (20 0 0);
+
-        Cp              CpInf;
+        // Conditional mandatory entries (runtime modifiable)
+        UInf            (10 0 0);
+
+        // Conditional optional entries (runtime modifiable)
+        Cp              <CpName>;
+        rho             <rhoName>;
+
+        // mandatory if Cp == CpInf
         CpInf           1005;
-        ...
+
+        // mandatory if rho == rhoInf
+        rhoInf          1;
+    }
     \endverbatim
 
-    Where the entries comprise:
+    where the entries mean:
     \table
-        Property     | Description             | Required    | Default value
+      Property  | Description                            | Type | Reqd | Dflt
-        type         | type name: heatTransferCoeff | yes    |
+      type      | Model name: ReynoldsAnalogy            | word | yes  | -
-        htcModel     | selected htc model      | yes         |
+      UInf      | Reference velocity                   | scalar | yes  | -
-        UInf         | reference velocity      | yes |
+      Cp      | Name of reference specific heat capacity | word | no   | Cp
-        Cp           | specific heat capacity field name | no |
+      CpInf   | Reference specific heat capacity value | scalar | cndtnl | -
-        rho          | density field name      | no |
+      rho     | Name of reference fluid density          | word | no   | rho
+      rhoInf  | Reference fluid density value          | scalar | cndtnl | -
     \endtable
 
-    Note:
+Note
   - to use a reference \c Cp, set \c Cp to \c CpInf
   - to use a reference \c rho, set \c rho to \c rhoInf
 
+See also
+  - Foam::heatTransferCoeffModel
+  - Foam::heatTransferCoeffModels::fixedReferenceTemperature
+  - Foam::heatTransferCoeffModels::localReferenceTemperature
+
 SourceFiles
     ReynoldsAnalogy.C
 
-SeeAlso
-    Foam::heatTransferCoeffModel
-
 \*---------------------------------------------------------------------------*/
 
 #ifndef heatTransferCoeffModels_ReynoldsAnalogy_H
@@ -138,13 +163,6 @@ protected:
         );
 
 
-        //- No copy construct
-        ReynoldsAnalogy(const ReynoldsAnalogy&) = delete;
-
-        //- No copy assignment
-        void operator=(const ReynoldsAnalogy&) = delete;
-
-
 public:
 
     //- Runtime type information
@@ -161,6 +179,12 @@ public:
             const word& TName
         );
 
+        //- No copy construct
+        ReynoldsAnalogy(const ReynoldsAnalogy&) = delete;
+
+        //- No copy assignment
+        void operator=(const ReynoldsAnalogy&) = delete;
+
 
     //- Destructor
     virtual ~ReynoldsAnalogy() = default;

src/functionObjects/field/heatTransferCoeff/heatTransferCoeffModels/fixedReferenceTemperature/fixedReferenceTemperature.C

@@ -85,8 +85,7 @@ void Foam::heatTransferCoeffModels::fixedReferenceTemperature::htc
     const FieldField<Field, scalar>& q
 )
 {
-    //const FieldField<Field, scalar> qBf(q());
+    const auto& T = mesh_.lookupObject<volScalarField>(TName_);
-    const volScalarField& T = mesh_.lookupObject<volScalarField>(TName_);
     const volScalarField::Boundary& Tbf = T.boundaryField();
     const scalar eps = ROOTVSMALL;
 

src/functionObjects/field/heatTransferCoeff/heatTransferCoeffModels/fixedReferenceTemperature/fixedReferenceTemperature.H

@@ -27,8 +27,8 @@ Class
     Foam::heatTransferCoeffModels::fixedReferenceTemperature
 
 Description
-    Heat transfer coefficient calculation that employs a fixed reference
+    Heat transfer coefficient calculation
-    temperature
+    that employs a fixed reference temperature.
 
     The heat transfer coefficient is specified by:
 
@@ -36,31 +36,43 @@ Description
         h = \frac{q}{T_{ref} - T_w}
     \f]
 
+    where
+    \vartable
+      h       | Convective heat transfer coefficient of the flow  [W/(m2 K)]
+      q       | Heat flux                                         [W/m2]
+      T_{ref} | Reference temperature of surrounding fluid        [K]
+      T_w     | Patch temperature                                 [K]
+    \endvartable
+
 Usage
-    Example of function object specification:
+    Minimal example by using \c system/controlDict.functions:
     \verbatim
-        type            heatTransferCoeff;
+    heatTransferCoeff1
-        libs            (fieldFunctionObjects);
+    {
+        // Mandatory and other optional entries
         ...
         htcModel        fixedReferenceTemperature;
-        TRef            300;
+
-        ...
+        // Conditional mandatory entries (runtime modifiable)
+        Tref            0;
+    }
     \endverbatim
 
-    Where the entries comprise:
+    where the entries mean:
     \table
-        Property     | Description                          | Required | Default
+      Property  | Description                            | Type | Reqd | Dflt
-        type         | type name: heatTransferCoeff         | yes |
+      type      | Model name: fixedReferenceTemperature  | word | yes  | -
-        htcModel     | selected htc model                   | yes |
+      Tref      | Reference temperature of surrounding fluid | scalar | yes | -
-        TRef         | reference temperature                | yes |
     \endtable
 
+See also
+  - Foam::heatTransferCoeffModel
+  - Foam::heatTransferCoeffModels::localReferenceTemperature
+  - Foam::heatTransferCoeffModels::ReynoldsAnalogy
+
 SourceFiles
     fixedReferenceTemperature.C
 
-SeeAlso
-    Foam::heatTransferCoeffModel
-
 \*---------------------------------------------------------------------------*/
 
 #ifndef heatTransferCoeffModels_fixedReferenceTemperature_H
@@ -100,12 +112,6 @@ protected:
             const FieldField<Field, scalar>& q
         );
 
-        //- No copy construct
-        fixedReferenceTemperature(const fixedReferenceTemperature&) = delete;
-
-        //- No copy assignment
-        void operator=(const fixedReferenceTemperature&) = delete;
-
 
 public:
 
@@ -123,6 +129,12 @@ public:
             const word& TName
         );
 
+        //- No copy construct
+        fixedReferenceTemperature(const fixedReferenceTemperature&) = delete;
+
+        //- No copy assignment
+        void operator=(const fixedReferenceTemperature&) = delete;
+
 
     //- Destructor
     virtual ~fixedReferenceTemperature() = default;

src/functionObjects/field/heatTransferCoeff/heatTransferCoeffModels/heatTransferCoeffModel/heatTransferCoeffModel.C

@@ -45,7 +45,7 @@ namespace Foam
 Foam::tmp<Foam::FieldField<Foam::Field, Foam::scalar>>
 Foam::heatTransferCoeffModel::q() const
 {
-    const volScalarField& T = mesh_.lookupObject<volScalarField>(TName_);
+    const auto& T = mesh_.lookupObject<volScalarField>(TName_);
     const volScalarField::Boundary& Tbf = T.boundaryField();
 
     auto tq = tmp<FieldField<Field, scalar>>::New(Tbf.size());
@@ -60,7 +60,7 @@ Foam::heatTransferCoeffModel::q() const
 
     if (mesh_.foundObject<cmpTurbModel>(cmpTurbModel::propertiesName))
     {
-        const cmpTurbModel& turb =
+        const auto& turb =
             mesh_.lookupObject<cmpTurbModel>(cmpTurbModel::propertiesName);
 
         const volScalarField& he = turb.transport().he();
@@ -76,7 +76,7 @@ Foam::heatTransferCoeffModel::q() const
     }
     else if (mesh_.foundObject<fluidThermo>(fluidThermo::dictName))
     {
-        const fluidThermo& thermo =
+        const auto& thermo =
             mesh_.lookupObject<fluidThermo>(fluidThermo::dictName);
 
         const volScalarField& he = thermo.he();
@@ -99,7 +99,7 @@ Foam::heatTransferCoeffModel::q() const
 
     // Add radiative heat flux contribution if present
 
-    const volScalarField* qrPtr = mesh_.cfindObject<volScalarField>(qrName_);
+    const auto* qrPtr = mesh_.cfindObject<volScalarField>(qrName_);
 
     if (qrPtr)
     {

src/functionObjects/field/heatTransferCoeff/heatTransferCoeffModels/heatTransferCoeffModel/heatTransferCoeffModel.H

@@ -35,9 +35,32 @@ Class
 Description
     An abstract base class for heat transfer coeffcient models.
 
+Usage
+    Minimal example by using \c system/controlDict.functions:
+    \verbatim
+    heatTransferCoeff1
+    {
+        // Mandatory and other optional entries
+        ...
+
+        // Mandatory (inherited) entries (runtime modifiable)
+        patches     (<patch1> <patch2> ... <patchN>);
+
+        // Optional (inherited) entries (runtime modifiable)
+        qr          <qrName>;
+    }
+    \endverbatim
+
+    where the entries mean:
+    \table
+      Property  | Description                  | Type | Reqd | Dflt
+      patches   | Names of operand patches  | wordRes | yes  | -
+      qr        | Name of radiative heat flux  | word | no   | qr
+    \endtable
+
 SourceFiles
-    heatTransferCoeffModel.C
+  - heatTransferCoeffModel.C
-    heatTransferCoeffModelNew.C
+  - heatTransferCoeffModelNew.C
 
 \*---------------------------------------------------------------------------*/
 
@@ -65,7 +88,7 @@ class heatTransferCoeffModel
 {
 protected:
 
-    // Public Data
+    // Protected Data
 
         //- Mesh reference
         const fvMesh& mesh_;
@@ -76,12 +99,10 @@ protected:
         //- Temperature name
         const word TName_;
 
-        //- Name of radiative heat flux (default = qr)
+        //- Name of radiative heat flux
         word qrName_;
 
 
-protected:
-
     // Protected Member Functions
 
         //- Set the heat transfer coefficient
@@ -91,12 +112,6 @@ protected:
             const FieldField<Field, scalar>& q
         ) = 0;
 
-        //- No copy construct
-        heatTransferCoeffModel(const heatTransferCoeffModel&) = delete;
-
-        //- No copy assignment
-        void operator=(const heatTransferCoeffModel&) = delete;
-
 
 public:
 
@@ -141,6 +156,12 @@ public:
             const word& TName
         );
 
+        //- No copy construct
+        heatTransferCoeffModel(const heatTransferCoeffModel&) = delete;
+
+        //- No copy assignment
+        void operator=(const heatTransferCoeffModel&) = delete;
+
 
     //- Destructor
     virtual ~heatTransferCoeffModel() = default;
@@ -172,7 +193,6 @@ public:
             return qrName_;
         }
 
-
         //- Read from dictionary
         virtual bool read(const dictionary& dict);
 

src/functionObjects/field/heatTransferCoeff/heatTransferCoeffModels/localReferenceTemperature/localReferenceTemperature.C

@@ -78,8 +78,7 @@ void Foam::heatTransferCoeffModels::localReferenceTemperature::htc
     const FieldField<Field, scalar>& q
 )
 {
-    ///const FieldField<Field, scalar> qBf(q());
+    const auto& T = mesh_.lookupObject<volScalarField>(TName_);
-    const volScalarField& T = mesh_.lookupObject<volScalarField>(TName_);
     const volScalarField::Boundary& Tbf = T.boundaryField();
     const scalar eps = ROOTVSMALL;
 

src/functionObjects/field/heatTransferCoeff/heatTransferCoeffModels/localReferenceTemperature/localReferenceTemperature.H

@@ -27,8 +27,8 @@ Class
     Foam::heatTransferCoeffModels::localReferenceTemperature
 
 Description
-    Heat transfer coefficient calculation that employs the patch internal
+    Heat transfer coefficient calculation that employs
-    field as the reference temperature
+    the patch internal field as the reference temperature.
 
     The heat transfer coefficient is specified by:
 
@@ -36,29 +36,39 @@ Description
         h = \frac{q}{T_c - T_w}
     \f]
 
+    where
+    \vartable
+      h       | Convective heat transfer coefficient of the flow  [W/(m2 K)]
+      q       | Heat flux                                         [W/m2]
+      T_{ref} | Reference temperature of patch internal field     [K]
+      T_w     | Patch temperature                                 [K]
+    \endvartable
+
 Usage
-    Example of function object specification:
+    Minimal example by using \c system/controlDict.functions:
     \verbatim
-        type            heatTransferCoeff;
+    heatTransferCoeff1
-        libs            (fieldFunctionObjects);
+    {
+        // Mandatory and other optional entries
         ...
         htcModel        localReferenceTemperature;
-        ...
+    }
     \endverbatim
 
-    Where the entries comprise:
+    where the entries mean:
     \table
-        Property     | Description             | Required    | Default value
+      Property  | Description                            | Type | Reqd | Dflt
-        type         | type name: heatTransferCoeff | yes    |
+      type      | Model name: localReferenceTemperature  | word | yes  | -
-        htcModel     | selected htc model      | yes         |
     \endtable
 
+See also
+  - Foam::heatTransferCoeffModel
+  - Foam::heatTransferCoeffModels::fixedReferenceTemperature
+  - Foam::heatTransferCoeffModels::ReynoldsAnalogy
+
 SourceFiles
     localReferenceTemperature.C
 
-SeeAlso
-    Foam::heatTransferCoeffModel
-
 \*---------------------------------------------------------------------------*/
 
 #ifndef heatTransferCoeffModels_localReferenceTemperature_H