From 4da3bf120cea62171e1777b764aed99e93b4c934 Mon Sep 17 00:00:00 2001
From: JGonzalez <jorge.gonzalez@upm.es>
Date: Mon, 13 Apr 2026 19:49:53 +0200
Subject: [PATCH] Structure for Neumann BC

---
 src/modules/mesh/moduleMesh.f90            | 27 ++++++++++++++++++++++
 src/modules/mesh/moduleMesh@boundaryEM.f90 | 21 +++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/src/modules/mesh/moduleMesh.f90 b/src/modules/mesh/moduleMesh.f90
index e257cf2..5fc6f2e 100644
--- a/src/modules/mesh/moduleMesh.f90
+++ b/src/modules/mesh/moduleMesh.f90
@@ -1056,6 +1056,33 @@ MODULE moduleMesh
 
   end interface
 
+  ! Neumann boundary condition (constant electric field normal to edge)
+  type, extends(boundaryEMGeneric):: boundaryEMNeumann
+    real(8):: electricField ! Electric field normal to the edge
+    contains
+      ! boundaryEMGeneric deferred procedures
+      procedure, pass:: apply => applyNeumann
+
+  end type boundaryEMNeumann
+
+  interface
+    module subroutine initNeumann(self, config, object)
+      use json_module
+
+      class(boundaryEMGeneric), allocatable, intent(inout):: self
+      type(json_file), intent(inout):: config
+      character(:), allocatable, intent(in):: object
+
+    end subroutine initNeumann
+
+    module subroutine applyNeumann(self, vectorF)
+      class(boundaryEMNeumann), intent(in):: self
+      real(8), intent(inout):: vectorF(:)
+
+    end subroutine applyNeumann
+
+  end interface
+
   ! Floating: Floating surface, ie, zero net current
   type, extends(boundaryEMGeneric):: boundaryEMFloating
     real(8):: potential
diff --git a/src/modules/mesh/moduleMesh@boundaryEM.f90 b/src/modules/mesh/moduleMesh@boundaryEM.f90
index f20804a..19dde6c 100644
--- a/src/modules/mesh/moduleMesh@boundaryEM.f90
+++ b/src/modules/mesh/moduleMesh@boundaryEM.f90
@@ -123,6 +123,27 @@ submodule(moduleMesh) boundaryEM
 
     end subroutine updateDirichletTime
 
+    ! Neumann constant value
+    ! Init
+    module subroutine initNeumann(self, config, object)
+      use json_module
+      implicit none
+
+      class(boundaryEMGeneric), allocatable, intent(inout):: self
+      type(json_file), intent(inout):: config
+      character(:), allocatable, intent(in):: object
+
+    end subroutine initNeumann
+
+    ! Apply
+    module subroutine applyNeumann(self, vectorF)
+      implicit none
+
+      class(boundaryEMNeumann), intent(in):: self
+      real(8), intent(inout):: vectorF(:)
+
+    end subroutine applyNeumann
+
     ! Floating surface
     ! Init
     module subroutine initFloating(self, config, object)