Impose homogeneous Dirichlet condition on the top and right surfaces, instead...

Impose homogeneous Dirichlet condition on the top and right surfaces, instead of homogeneous Neumann. It's a bit more natural, amd it matches the small example in the getdp documentation.

Electrostatics/microstrip.pro

@@ -35,12 +35,13 @@
    (called "Electrode" below) and to 0 V on the ground. A homogeneous Neumann
    boundary condition (zero flux of the displacement field, i.e. n.d = 0) is
    imposed on the left boundary of the domain to account for the symmetry of the
-   problem, as well as on the top and right boundaries that truncate the
-   simulation domain. */
+   problem. The domain is truncated on the top and right with a homogeneous
+   Dirichlet boundary condition (v = 0), assumed to be imposed sufficiently far
+   away from the microstrip. */
 
 Group {
   /* One starts by giving explicit meaningful names to the Physical regions
-     defined in the "microstrip.msh" mesh file. This model comprises only 
+     defined in the "microstrip.msh" mesh file. This model comprises only
      2 volume regions and 2 surface regions. */
 
   Air = Region[101];
@@ -48,6 +49,7 @@ Group {
 
   Ground = Region[120];
   Electrode = Region[121];
+  SurfInf = Region[130];
 
   /* We now define abstract regions to be used below in the definition of the
      scalar electric potential formulation:
@@ -61,9 +63,9 @@ Group {
 
      Since there are no non-homogeneous Neumann conditions in this particular
      example, Sur_Neu_Ele is defined as empty.
-     
-     Note that volume elements are those that correspond to the higher dimension 
-     of the model at hand (2D elements here), surface elements correspond to the 
+
+     Note that volume elements are those that correspond to the higher dimension
+     of the model at hand (2D elements here), surface elements correspond to the
      higher dimension of the model minus one (1D elements here).
      */
 
@@ -82,7 +84,7 @@ Function {
 }
 
 Constraint {
-  /* The Dirichlet boundary condition is also defined piecewise.  
+  /* The Dirichlet boundary condition is also defined piecewise.
      The constraint "Dirichlet_Ele" is invoked in the FunctionSpace
      below. */
 
@@ -90,6 +92,7 @@ Constraint {
     Case {
       { Region Ground; Value 0.; }
       { Region Electrode; Value 1.e-3; }
+      { Region SurfInf; Value 0; }
     }
   }
 }
@@ -131,7 +134,7 @@ FunctionSpace {
       { Name sn; NameOfCoef vn; Function BF_Node;
         Support Dom_Hgrad_v_Ele; Entity NodesOf[ All ]; }
       // using "NodesOf[All]" instead of "NodesOf[Dom_Hgrad_v_Ele]" is an
-      // optimization, which avoids explicitly building the list of 
+      // optimization, which avoids explicitly building the list of
       // all the nodes
     }
     Constraint {
@@ -234,7 +237,7 @@ Formulation {
      expressions than the second one. In our case it should be expressed in
      terms of the FE expansion of "v" at the present system solution, i.e. when
      the coefficients vn_k in the expansion of "v = Sum_k vn_k sn_k" are
-     unknown. This is indicated by prefixing the braces with "Dof" (degrees of 
+     unknown. This is indicated by prefixing the braces with "Dof" (degrees of
      freedom), which leads to the following density:
 
      [ epsilon[] * Dof{d v} , {d v} ],
@@ -252,7 +255,7 @@ Formulation {
      a so-called linear term that contributes to the right-hand side of the
      linear system.
 
-     Both choices are commonly used in different contexts, and we shall often 
+     Both choices are commonly used in different contexts, and we shall often
      come back in subsequent tutorials. */
 
   { Name Electrostatics_v; Type FemEquation;
@@ -270,13 +273,13 @@ Formulation {
       Integral { [ nd[] , {v} ];
 	    In Sur_Neu_Ele; Jacobian Sur; Integration Int; }
 
-      All the terms in the Equation environment are added, 
+      All the terms in the Equation environment are added,
       and an implicit "= 0" is considered at the end. */
     }
   }
 }
 
-/* In the Resolution environment we specify what to do with a weak formulation: 
+/* In the Resolution environment we specify what to do with a weak formulation:
    here we simply generate a linear system, solve it and save the solution (.res file)
    to disk. */
 

ElectrostaticsFloating/floating.pro

@@ -85,11 +85,13 @@ Function {
 }
 
 Constraint {
-  /* The Dirichlet boundary condition on the local electric potential is no
-     longer used. The microstrip and the ground are herein treated as electrodes,
-     whose voltage is imposed with the "SetGlobalPotential" constraint below. */
+  /* The Dirichlet boundary condition on the local electric potential is only
+     used for the homogeneous condition on the top and right boundaries. The
+     microstrip and the ground are now treated as electrodes, whose voltage is
+     imposed with the "SetGlobalPotential" constraint below. */
   { Name Dirichlet_Ele; Type Assign;
     Case {
+      { Region SurfInf; Value 0; }
     }
   }