using DpDt and adding run-time modifiable timestep support

applications/solvers/heatTransfer/buoyantFoam/buoyantFoam.C

@@ -48,6 +48,9 @@ int main(int argc, char *argv[])
 #   include "readEnvironmentalProperties.H"
 #   include "createFields.H"
 #   include "initContinuityErrs.H"
+#   include "readTimeControls.H"
+#   include "compressibleCourantNo.H"
+#   include "setInitialDeltaT.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -55,11 +58,13 @@ int main(int argc, char *argv[])
 
     while (runTime.run())
     {
+#       include "readTimeControls.H"
 #       include "readPISOControls.H"
 #       include "compressibleCourantNo.H"
-//#       include "setDeltaT.H"
+#       include "setDeltaT.H"
 
         runTime++;
+
         Info<< "Time = " << runTime.timeName() << nl << endl;
 
 #       include "rhoEqn.H"

applications/solvers/heatTransfer/buoyantFoam/createFields.H

@@ -52,8 +52,9 @@
         )
     );
 
-    Info<< "Creating field dpdt\n" << endl;
+    Info<< "Creating field DpDt\n" << endl;
-    volScalarField dpdt = fvc::ddt(p);
+    volScalarField DpDt =
+        fvc::DDt(surfaceScalarField("phiU", phi/fvc::interpolate(rho)), p);
 
     Info<< "Calculating field g.h\n" << endl;
     volScalarField gh("gh", g & mesh.C());

applications/solvers/heatTransfer/buoyantFoam/hEqn.H

@@ -5,9 +5,7 @@
       + fvm::div(phi, h)
       - fvm::laplacian(turbulence->alphaEff(), h)
      ==
-        dpdt
+        DpDt
-      + fvc::div(phi/fvc::interpolate(rho)*fvc::interpolate(p))
-      - p*fvc::div(phi/fvc::interpolate(rho))
     );
 
     hEqn.relax();

applications/solvers/heatTransfer/buoyantFoam/pEqn.H

@@ -40,7 +40,7 @@ for (int nonOrth=0; nonOrth<=nNonOrthCorr; nonOrth++)
 }
 
 p == pd + rho*gh + pRef;
-dpdt = fvc::ddt(p);
+DpDt = fvc::DDt(surfaceScalarField("phiU", phi/fvc::interpolate(rho)), p);
 
 #include "rhoEqn.H"
 #include "compressibleContinuityErrs.H"