ENH: pessureTools function object - updated coeff calculation and usage documentation

src/postProcessing/functionObjects/utilities/pressureTools/pressureTools.C

@@ -154,15 +154,20 @@ Foam::tmp<Foam::volScalarField> Foam::pressureTools::pDyn
 
 Foam::tmp<Foam::volScalarField> Foam::pressureTools::convertToCoeff
 (
-    const volScalarField& pCalculated,
+    const volScalarField& p
-    const volScalarField& pIn
 ) const
 {
-    tmp<volScalarField> tCoeff(pCalculated);
+    tmp<volScalarField> tCoeff(p);
 
     if (calcCoeff_)
     {
-        tCoeff() /= pDyn(pIn) + dimensionedScalar("p0", dimPressure, SMALL);
+        tCoeff() -= dimensionedScalar("pInf", dimPressure, pInf_);
+
+        const dimensionedScalar p0("p0", dimPressure, SMALL);
+        const dimensionedVector U("U", dimVelocity, UInf_);
+        const dimensionedScalar rho("rho", dimDensity, rhoInf_);
+
+        tCoeff() /= 0.5*rho*magSqr(U) + p0;
     }
 
     return tCoeff;
@@ -182,13 +187,16 @@ Foam::pressureTools::pressureTools
     name_(name),
     obr_(obr),
     active_(true),
-    calcTotal_(false),
-    calcCoeff_(false),
     pName_("p"),
     UName_("U"),
     rhoName_("rho"),
+    rhoRef_(1.0),
+    calcTotal_(false),
     pRef_(0.0),
-    rhoRef_(1.0)
+    calcCoeff_(false),
+    pInf_(0.0),
+    UInf_(vector::zero),
+    rhoInf_(0.0)
 {
     // Check if the available mesh is an fvMesh, otherwise deactivate
     if (!isA<fvMesh>(obr_))
@@ -241,6 +249,12 @@ void Foam::pressureTools::read(const dictionary& dict)
         }
 
         dict.lookup("calcCoeff") >> calcCoeff_;
+        if (calcCoeff_)
+        {
+            dict.lookup("pInf") >> pInf_;
+            dict.lookup("UInf") >> UInf_;
+            dict.lookup("rhoInf") >> rhoInf_;
+        }
     }
 }
 
@@ -272,7 +286,7 @@ void Foam::pressureTools::write()
                 obr_,
                 IOobject::NO_READ
             ),
-            convertToCoeff(rhoScale(p)*p + pDyn(p) + pRef(), p)
+            convertToCoeff(rhoScale(p)*p + pDyn(p) + pRef())
         );
 
         pResult.write();

src/postProcessing/functionObjects/utilities/pressureTools/pressureTools.H

@@ -41,15 +41,40 @@ Description
         \f]
     - static pressure coefficient
         \f[
-            Cp_s = \frac{p_s}{0.5 \rho |U|^2}
+            Cp_s = \frac{p_s - p_{\inf}}{0.5 \rho_{\inf} |U_{\inf}|^2}
         \f]
     - total pressure coefficient
         \f[
-            Cp_T = \frac{p_T}{0.5 \rho |U|^2}
+            Cp_T = \frac{p_T - p_{\inf}}{0.5 \rho_{\inf} |U_{\inf}|^2}
         \f]
 
-    The function object will operate on both kinematic (p_k) and static
+    where
-    pressure (p_s) fields, and the result is written as a volScalarField.
+    \vartable
+        \rho        | density [kg/m3]
+        U           | velocity [m/s]
+        \rho_{\inf} | freestream density [kg/m3]
+        p_{\inf}    | freestream pressure [Pa]
+        U_{\inf}    | freestream velocity [m/s]
+        p_k         | kinematic pressure (p/rho)[m2/s2]
+        p_s         | pressure [Pa]
+        p_T         | total pressure [Pa]
+        p_{ref}     | reference pressure level [Pa]
+        Cp_{s}      | pressure coefficient
+        Cp_{T}      | total pressure coefficient
+    \endvartable
+
+    The function object will operate on both kinematic (\f$ p_k \f$) and static
+    pressure (\f$ p_s \f$) fields, and the result is written as a
+    volScalarField.
+
+    The modes of operation are:
+    \table
+        Mode                        | calcTotal | calcCoeff  
+        static pressure             | no        | no
+        total pressure              | yes       | no
+        pressure coefficient        | no        | yes
+        total pressure coefficient  | yes       | yes
+    \endtable
 
     Example of function object specification to calculate pressure coefficient:
     \verbatim
@@ -67,10 +92,13 @@ Description
     \table
         Property     | Description             | Required    | Default value
         type         | type name: pressureTools| yes         |
-        calcCoeff    | Calculate pressure coefficient | yes  |
-        calcTotal    | Calculate total coefficient | yes     |
         rhoRef       | Reference density for incompressible cases | no | 1
-        pRef         | Reference pressure for total pressure |no| 0.0
+        calcTotal    | Calculate total coefficient | yes     |
+        pRef         | Reference pressure for total pressure | no | 0.0
+        calcCoeff    | Calculate pressure coefficient | yes  |
+        pInf         | Freestream pressure for coefficient calculation | no |
+        UInf         | Freestream velocity for coefficient calculation | no |
+        rhoInf       | Freestream density for coefficient calculation | no |
     \endtable
 
 SourceFiles
@@ -113,12 +141,6 @@ class pressureTools
         //- On/off switch
         bool active_;
 
-        //- Flag to calculate total pressure
-        bool calcTotal_;
-
-        //- Flag to calculate pressure coefficient
-        bool calcCoeff_;
-
         //- Name of pressure field, default is "p"
         word pName_;
 
@@ -128,13 +150,34 @@ class pressureTools
         //- Name of density field, default is "rho"
         word rhoName_;
 
-        //- Reference pressure level (used for total pressure)
+        //- Reference density employed for incompressible cases
-        scalar pRef_;
-
-        //- Reference density value
         scalar rhoRef_;
 
 
+        // Total pressure calculation
+
+            //- Flag to calculate total pressure
+            bool calcTotal_;
+
+            //- Reference pressure level
+            scalar pRef_;
+
+
+        // Pressure coefficient calculation
+
+            //- Flag to calculate pressure coefficient
+            bool calcCoeff_;
+
+            //- Freestream pressure
+            scalar pInf_;
+
+            //- Freestream velocity
+            vector UInf_;
+
+            //- Freestream density
+            scalar rhoInf_;
+
+
     // Private Member Functions
 
         //- Return the name of the derived pressure field
@@ -152,12 +195,8 @@ class pressureTools
         //- Calculate and return the dynamic pressure
         tmp<volScalarField> pDyn(const volScalarField& p) const;
 
-        //- Convert to coeff data by applying the pDyn scaling
+        //- Convert to coeff by applying the freestream dynamic pressure scaling
-        tmp<volScalarField> convertToCoeff
+        tmp<volScalarField> convertToCoeff(const volScalarField& p) const;
-        (
-            const volScalarField& pCalculated,
-            const volScalarField& pIn
-        ) const;
 
         //- Disallow default bitwise copy construct
         pressureTools(const pressureTools&);