Small fixes addressing comments.

* correcting species transport equation
* making check for laminar turbulence compatible with OF-4.0 and OF-5.0

applications/solvers/testTwoFluidRecurrenceTurbulence/CEqn.H

@@ -4,10 +4,14 @@
     The recurrence-based turbulence models are derived from the standard base classes 
     of OpenFOAM, thus they behave as a normal turbulence model would.
 */
+
+alphaRhoPhiCarrier = linearInterpolate(alpha2*rhoCarrier)*phi2;
+
 fvScalarMatrix CEqn
 (
 	fvm::ddt(alphaCarrier*rhoCarrier, C)
-  + fvm::div(linearInterpolate(alpha2*rhoCarrier)*phi2, C, "div(alphaRhoPhi,C)")
+  + fvm::div(alphaRhoPhiCarrier, C, "div(alphaRhoPhi,C)")
+  - fvm::Sp(fvc::div(alphaRhoPhiCarrier), C)
 
   - fvm::laplacian
 	(

applications/solvers/testTwoFluidRecurrenceTurbulence/checkTurbulenceModels.H

@@ -12,11 +12,11 @@
             << phase.turbulence().type() << endl;
         
         /*
-            Use appropriate if-statement for OpenFOAM-4.0 resp. OpenFOAM-5.0,
-            as the laminar, multi-phase turbulence model is named Stokes in OF-5.0
+            Check for laminar turbulence. This works with OpenFOAM-4.0 and OpenFOAM-5.0,
+            as the laminar, multi-phase turbulence model is named "laminar" in OF-4.0
+            and "Stokes" in OF-5.0
         */
-        //if (phase.turbulence().type() == "Stokes") // OpenFOAM-5.0
-        if (phase.turbulence().type() == "laminar") // OpenFOAM-4.0
+        if (phase.turbulence().type() == "laminar" || phase.turbulence().type() == "Stokes")
         {
             // do nothing
         }