Delayed initialisation of the immersed boundary patch: avoid cutting at patchField initialisation and delay until fvMesh init

src/immersedBoundary/immersedBoundary/immersedBoundaryFvPatch/immersedBoundaryFvPatch.C

@@ -360,6 +360,18 @@ Foam::label Foam::immersedBoundaryFvPatch::size() const
 {
     // Immersed boundary patch size equals to the number of intersected cells
     // HJ, 28/Nov/2017
+
+    // Note: asking for patch size triggers the cutting which involves
+    // parallel communication.  This should be avoided under read/write, ie
+    // when the ibPolyPatch_ is not initialised.
+    // Initialisation happens when the fvMesh is initialised, which should be
+    // sufficient
+    //  HJ, 12/Dec/2018
+    if (!ibPolyPatch_.active())
+    {
+        return 0;
+    }
+
     return ibPolyPatch_.ibCells().size();
 }
 
@@ -371,16 +383,4 @@ Foam::immersedBoundaryFvPatch::faceCells() const
 }
 
 
-// Foam::tmp<Foam::vectorField> Foam::immersedBoundaryFvPatch::nf() const
-// {
-//     return ibPolyPatch_.ibPatch().faceNormals();
-// }
-
-
-// Foam::tmp<Foam::vectorField> Foam::immersedBoundaryFvPatch::delta() const
-// {
-//     return ibPolyPatch_.ibPatch().faceCentres() - ibPolyPatch_.ibCellCentres();
-// }
-
-
 // ************************************************************************* //

src/immersedBoundary/immersedBoundary/immersedBoundaryFvPatch/immersedBoundaryFvPatch.H

@@ -153,6 +153,9 @@ public:
         // Access
 
             //- Return size equal to number of intersected cells
+            //  Note: if the ibPolyPatch is not initialised, return zero size
+            // to avoid triggering cutting (with parallel communications).
+            //  HJ, 12/Dec/2018
             virtual label size() const;
 
             //- Return patch slice size
@@ -167,17 +170,6 @@ public:
             virtual const unallocLabelList& faceCells() const;
 
 
-        // Access functions for geometrical data
-
-            // //- Return face normals
-            // //  Reconsider. HJ, 11/Dec/2017
-            // tmp<vectorField> nf() const;
-
-            // //- Return cell-centre to face-centre vector
-            // //  Reconsider. HJ, 11/Dec/2017
-            // virtual tmp<vectorField> delta() const;
-
-
         // Access to immersed boundary components
 
             //- Return reference to immersed boundary polyPatch

src/immersedBoundary/immersedBoundary/immersedBoundaryFvPatchFields/basic/fixedValueIbFvPatchField/fixedValueIbFvPatchField.C

@@ -66,7 +66,7 @@ fixedValueIbFvPatchField<Type>::fixedValueIbFvPatchField
     const dictionary& dict
 )
 :
-    fixedValueFvPatchField<Type>(p, iF),   // Do not read mixed data
+    fixedValueFvPatchField<Type>(p, iF, dict),
     immersedBoundaryFieldBase<Type>
     (
         p,
@@ -115,7 +115,7 @@ fixedValueIbFvPatchField<Type>::fixedValueIbFvPatchField
     const fvPatchFieldMapper& mapper
 )
 :
-    fixedValueFvPatchField<Type>(p, iF),  // Do not map mixed data
+    fixedValueFvPatchField<Type>(p, iF),  // Do not map fixed data
     immersedBoundaryFieldBase<Type>
     (
         p,

src/immersedBoundary/immersedBoundary/immersedBoundaryFvPatchFields/basic/mixedIbFvPatchField/mixedIbFvPatchField.C

@@ -70,7 +70,7 @@ mixedIbFvPatchField<Type>::mixedIbFvPatchField
     const dictionary& dict
 )
 :
-    mixedFvPatchField<Type>(p, iF),   // Do not read mixed data
+    mixedFvPatchField<Type>(p, iF),
     immersedBoundaryFieldBase<Type>
     (
         p,
@@ -105,15 +105,17 @@ mixedIbFvPatchField<Type>::mixedIbFvPatchField
             << exit(FatalIOError);
     }
 
-    // Re-interpolate the data related to immersed boundary
-    this->updateIbValues();
-
-    // mixedFvPatchField<Type>::evaluate();
-
-    // On creation of the field, intersection cannot be called.
+    // On creation of the field, intersection cannot be called unless
+    // the patch is active
     // Initialise the value to avoid errors
     // HJ, 1/Dec/2017
-    Field<Type>::operator=(pTraits<Type>::zero);
+    if (this->ibPatch().ibPolyPatch().active())
+    {
+        // Re-interpolate the data related to immersed boundary
+        this->updateIbValues();
+
+        mixedFvPatchField<Type>::evaluate();
+    }
 }
 
 

src/immersedBoundary/immersedBoundary/immersedBoundaryFvPatchFields/derived/movingImmersedBoundaryVelocity/movingImmersedBoundaryVelocityFvPatchVectorField.C

@@ -65,7 +65,7 @@ movingImmersedBoundaryVelocityFvPatchVectorField
     const dictionary& dict
 )
 :
-    fixedValueFvPatchVectorField(p, iF),   // Do not read data
+    fixedValueFvPatchVectorField(p, iF, dict),
     immersedBoundaryFieldBase<vector>
     (
         p,

src/immersedBoundary/immersedBoundary/immersedBoundaryFvsPatchFields/immersedBoundaryFvsPatchField/immersedBoundaryFvsPatchField.C

@@ -66,11 +66,9 @@ immersedBoundaryFvsPatchField<Type>::immersedBoundaryFvsPatchField
     const dictionary& dict
 )
 :
-    fvsPatchField<Type>(p, iF),   // Do not read base data
+    fvsPatchField<Type>(p, iF, dict),
     ibPatch_(refCast<const immersedBoundaryFvPatch>(p))
-{
-    operator=(pTraits<Type>::zero);
-}
+{}
 
 
 template<class Type>

src/immersedBoundary/immersedBoundary/immersedBoundaryPolyPatch/immersedBoundaryPolyPatch.H

@@ -308,6 +308,13 @@ public:
 
         // Immersed boundary patch data
 
+            //- Is the immersed boundary patch active?
+            //  (is the intersection patch calculated?)
+            bool active() const
+            {
+                return ibPatchPtr_ != NULL;
+            }
+
             //- Return primitivePatch of cell-intersected faces
             //  Faces are calculated as intesection between the volume mesh
             //  and the ibMesh