ENH: refineMesh: user-specified coordinate system

etc/caseDicts/annotated/refineMeshDict

@@ -22,12 +22,15 @@ set c0;
 //   x,y,z axis. Specify in globalCoeffs section below.
 // - patchLocal : coordinate system different for every cell. Specify in
 //   patchLocalCoeffs section below.
+// - user : coordinate system provided. Usually cylindrical or spherical.
+//   Specify in userCoeffs section below.
 // - fieldBased : uses the list of field names from the directions list for
 //   selecting the directions to cut. Meant to be used with geometricCut, but
 //   can also be used with useHexTopology.
 coordinateSystem global;
 //coordinateSystem patchLocal;
 //coordinateSystem fieldBased;
+//coordinateSystem user;
 
 // .. and its coefficients. x,y in this case. (normal direction is calculated
 // as tan1^tan2)
@@ -43,6 +46,15 @@ patchLocalCoeffs
     tan1 (1 0 0);
 }
 
+userCoeffs
+{
+    type    cylindrical;
+    origin  (0 0 0);
+    e1      (1 0 0);    // tan1 direction
+    e3      (0 1 0);    // normal direction
+}
+
+
 // List of directions to refine, if global or patchLocal
 directions
 (

src/dynamicMesh/meshCut/directions/directions.C

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020,2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,6 +35,7 @@ License
 #include "meshTools.H"
 #include "hexMatcher.H"
 #include "globalMeshData.H"
+#include "coordinateSystem.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
@@ -341,6 +342,30 @@ Foam::directions::directions
             operator[](nDirs++) = vectorField(1, tan2);
         }
     }
+    else if (coordSystem == "user")
+    {
+        const dictionary& globalDict = dict.subDict("userCoeffs");
+
+        auto csysPtr(coordinateSystem::New(mesh.thisDb(), globalDict));
+        const auto& cs = csysPtr();
+
+        if (wantNormal)
+        {
+            // 'Normal' is usually e3.
+            vectorField& result = operator[](nDirs++);
+            result = cs.transform(mesh.cellCentres(), vector(0, 0, 1));
+        }
+        if (wantTan1)
+        {
+            vectorField& result = operator[](nDirs++);
+            result = cs.transform(mesh.cellCentres(), vector(1, 0, 0));
+        }
+        if (wantTan2)
+        {
+            vectorField& result = operator[](nDirs++);
+            result = cs.transform(mesh.cellCentres(), vector(0, 1, 0));
+        }
+    }
     else if (coordSystem == "patchLocal")
     {
         const dictionary& patchDict = dict.subDict("patchLocalCoeffs");

src/dynamicMesh/meshCut/directions/directions.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -31,10 +31,11 @@ Description
     Set of directions for each cell in the mesh. Either uniform and size=1
     or one set of directions per cell.
 
-    Used in splitting cells.
-    Either all cells have similar refinement direction ('global') or
-    direction is dependent on local cell geometry, or loads selected fields
-    by name ('fieldBased'). Controlled by dictionary.
+    Used in splitting cells. Options:
+    - global        : global xyz coordinate system
+    - user          : user-defined coordinate system
+    - patchLocal    : normal direction from (flat) given patch
+    - fieldBased    : supply separate vectorIOField for each direction
 
 SourceFiles
     directions.C