snappyHexMeshConfig: added '-firstLayerThickness' and '-layerExpansionRatio' options

applications/utilities/preProcessing/snappyHexMeshConfig/snappyHexMeshConfig.C

@@ -140,6 +140,12 @@ Usage
       - \par -layers \<int\>
         Specify <int> surface layers at wall boundaries, default 0
 
+      - \par -firstLayerThickness \<value\>
+        Specify the thickness of the near wall cells for layer addition
+
+      - \par -layerExpansionRatio \<value\>
+        Specify the expansion ratio between layers, default 1.2
+
       - \par -cellZones \<list\>
         Surfaces that form cellZones, e.g. '(porousZone heatSource)'
 
@@ -197,7 +203,7 @@ void readPatchOption
 
 int main(int argc, char *argv[])
 {
-    argList::usageMin = 30;
+    argList::usageMin = 32;
     argList::usageMax = 105;
 
     argList::addNote
@@ -320,6 +326,20 @@ int main(int argc, char *argv[])
         "specify <int> surface layers at wall boundaries, default 0"
     );
 
+    argList::addOption
+    (
+        "firstLayerThickness",
+        "value",
+        "specify the thickness of the near wall cells for layer addition"
+    );
+
+    argList::addOption
+    (
+        "layerExpansionRatio",
+        "value",
+        "specify the expansion ratio between layers, default 1.2"
+    );
+
     argList::addOption
     (
         "cellZones",
@@ -574,6 +594,16 @@ int main(int argc, char *argv[])
 
     const label layers(args.optionLookupOrDefault<label>("layers", 0));
 
+    const scalar firstLayerThickness
+    (
+        args.optionLookupOrDefault<scalar>("firstLayerThickness", 0)
+    );
+
+    const scalar layerExpansionRatio
+    (
+        args.optionLookupOrDefault<scalar>("layerExpansionRatio", 1.2)
+    );
+
     const point insidePoint
     (
         args.optionLookupOrDefault<point>("insidePoint", point::zero)
@@ -610,6 +640,8 @@ int main(int argc, char *argv[])
         refinementDists,
         explicitFeatures,
         layers,
+        firstLayerThickness,
+        layerExpansionRatio,
         insidePoint,
         nCellsBetweenLevels
     );

applications/utilities/preProcessing/snappyHexMeshConfig/snappyHexMeshConfiguration.C

@@ -459,13 +459,36 @@ void Foam::snappyHexMeshConfiguration::writeAddLayersControls()
 
     endDict(os_);
 
-    os_ << indent << "relativeSizes       on; "
-        << "// off, usually with firstLayerThickness" << nl
-        << indent << "expansionRatio      1.2;" << nl
-        << indent << "finalLayerThickness 0.5;" << nl
-        << indent << "minThickness        1e-3;" << nl
-        << indent << "firstLayerThickness-disabled 0.01;" << nl << nl
-        << indent << "maxThicknessToMedialRatio-disabled 0.3;" << endl;
+    bool relativeSizes(firstLayerThickness_ == 0);
+
+    // relativeSizes
+    os_ << indent << "relativeSizes       "
+        << (
+                relativeSizes
+              ? "on; // off, usually with firstLayerThickness"
+              : "off; // on, usually with finalLayerThickness"
+           ) << endl;
+
+    // expansionRatio
+    os_ << indent << "expansionRatio      "<< layerExpansionRatio_
+        << ";" << endl;
+
+    // finalLayerThickness
+    os_ << indent << "finalLayerThickness"
+        << (relativeSizes ? " " : "-disabled ") << "0.5;" << endl;
+
+    // minimumThickness
+    os_ << indent << "minThickness        "
+        << (relativeSizes ? scalar(0.001) : 0.5*firstLayerThickness_)
+        << ";" << endl;
+
+    // firstLayerThickness
+    os_ << indent << "firstLayerThickness"
+        << (relativeSizes ? "-disabled " : " ")
+        << firstLayerThickness_ << ";" << endl;
+
+    // maxThicknessToMedialRatio
+    os_ << indent << "maxThicknessToMedialRatio-disabled 0.3;" << endl;
 
     endDict(os_);
 }
@@ -499,6 +522,8 @@ Foam::snappyHexMeshConfiguration::snappyHexMeshConfiguration
     const List<Tuple3<word, scalar, label>>& refinementDists,
     const bool explicitFeatures,
     const label layers,
+    const scalar firstLayerThickness,
+    const scalar layerExpansionRatio,
     const point& insidePoint,
     const label nCellsBetweenLevels
 )
@@ -512,6 +537,8 @@ Foam::snappyHexMeshConfiguration::snappyHexMeshConfiguration
     refinementDists_(refinementDists),
     explicitFeatures_(explicitFeatures),
     layers_(layers),
+    firstLayerThickness_(firstLayerThickness),
+    layerExpansionRatio_(layerExpansionRatio),
     insidePoint_(insidePoint),
     nCellsBetweenLevels_(nCellsBetweenLevels)
 {}

applications/utilities/preProcessing/snappyHexMeshConfig/snappyHexMeshConfiguration.H

@@ -86,6 +86,12 @@ class snappyHexMeshConfiguration
         //- Number of layers at wall patches, default 0
         const label layers_;
 
+        //- Thickness of the near wall cells with layer addition
+        const scalar firstLayerThickness_;
+
+        //- Expansion ratio used with layer addition
+        const scalar layerExpansionRatio_;
+
         //- insidePoint parameter
         point insidePoint_;
 
@@ -175,6 +181,8 @@ public:
             const List<Tuple3<word, scalar, label>>& refinementDists,
             const bool explicitFeatures,
             const label layers,
+            const scalar firstLayerThickness,
+            const scalar layerExpansionRatio,
             const point& insidePoint,
             const label nCellsBetweenLevels
         );