BUG: Corrected porosity force initialisation

src/finiteVolume/cfdTools/general/porosityModel/DarcyForchheimer/DarcyForchheimer.C

@@ -130,8 +130,8 @@ void Foam::porosityModels::DarcyForchheimer::calcForce
     vectorField& force
 ) const
 {
-    scalarField Udiag(U.size());
-    vectorField Usource(U.size());
+    scalarField Udiag(U.size(), 0.0);
+    vectorField Usource(U.size(), vector::zero);
     const scalarField& V = mesh_.V();
 
     apply(Udiag, Usource, V, rho, mu, U);

src/finiteVolume/cfdTools/general/porosityModel/fixedCoeff/fixedCoeff.C

@@ -183,8 +183,8 @@ void Foam::porosityModels::fixedCoeff::calcForce
     vectorField& force
 ) const
 {
-    scalarField Udiag(U.size());
-    vectorField Usource(U.size());
+    scalarField Udiag(U.size(), 0.0);
+    vectorField Usource(U.size(), vector::zero);
     const scalarField& V = mesh_.V();
     scalar rhoRef = readScalar(coeffs_.lookup("rhoRef"));
 

src/finiteVolume/cfdTools/general/porosityModel/powerLaw/powerLaw.C

@@ -74,7 +74,7 @@ void Foam::porosityModels::powerLaw::calcForce
     vectorField& force
 ) const
 {
-    scalarField Udiag(U.size());
+    scalarField Udiag(U.size(), 0.0);
     const scalarField& V = mesh_.V();
 
     apply(Udiag, V, rho, U);