[pointsource] Explicitly divide by source embeddings for better transparency

dumux/common/fvproblem.hh

@@ -418,7 +418,7 @@ public:
                 // call convienience problem interface function
                 asImp_().pointSource(pointSource, element, fvGeometry, elemVolVars, scv);
                 // at last take care about multiplying with the correct volume
-                pointSource /= volume;
+                pointSource /= volume*pointSource.embeddings();
                 // add the point source values to the local residual
                 source += pointSource.values();
             }

dumux/common/pointsource.hh

@@ -115,14 +115,8 @@ public:
     }
 
     //! return the source values
-    // don't forget to call this when it's overloaded
-    // in the derived class
     PrimaryVariables values() const
-    {
-        auto values = PrimaryVariables(values_);
-        values /= embeddings_;
-        return values;
-    }
+    { return values_; }
 
     //! return the source position
     const GlobalPosition& position() const
@@ -144,7 +138,17 @@ public:
         embeddings_ = embeddings;
     }
 
-    //! get the number of embeddings for this point source
+    /*!
+     * \brief get the number of embeddings for this point source
+     * \note A point source might be located on the intersection between several scvs.
+     *       If so, there are point sources for every neighboring scv with the same position.
+     *       `embeddings` returns the number of neighboring scvs.
+     * Example: If I want to inject 1kg/s at a location that is on the inner face of an scv
+     *          the point source exists in both scvs. Both have a value of 1kg/s.
+     *          We then divide the value by the number of embeddings to not inject 2kg/s but 1kg/s.
+     * \note This division is done in the problem.scvPointSources() if this behaviour is not explicitly
+     *       changed by e.g. overloading this function in the problem implementation.
+     */
     std::size_t embeddings() const
     {
         return embeddings_;