twoPhaseEulerFoam tutorials: updated to ensure particle phase-fraction conservation

tutorials/multiphase/twoPhaseEulerFoam/RAS/fluidisedBed/0/U.particles

@@ -28,9 +28,8 @@ boundaryField
 
     outlet
     {
-        type               pressureInletOutletVelocity;
-        phi                phi.particles;
-        value              $internalField;
+        type               fixedValue;
+        value              uniform (0 0 0);
     }
 
     walls

tutorials/multiphase/twoPhaseEulerFoam/RAS/fluidisedBed/0/alpha.particles

@@ -6027,8 +6027,7 @@ boundaryField
 {
     inlet
     {
-        type            fixedValue;
-        value           uniform 0;
+        type            zeroGradient;
     }
     outlet
     {

tutorials/multiphase/twoPhaseEulerFoam/RAS/fluidisedBed/system/fvSolution

@@ -25,7 +25,7 @@ solvers
 
         solver          PCG;
         preconditioner  DIC;
-        tolerance       1e-6;
+        tolerance       1e-9;
         relTol          0;
     }
 

tutorials/multiphase/twoPhaseEulerFoam/laminar/fluidisedBed/system/fvSolution

@@ -25,7 +25,7 @@ solvers
 
         solver          PCG;
         preconditioner  DIC;
-        tolerance       1e-6;
+        tolerance       1e-9;
         relTol          0;
     }