Developer's-corner/Boundary-Conditions.md

@@ -20,14 +20,15 @@ Disk {
 ```
 
 **FargOCA** will then invoke those boundaries condition at predefined place in the code. 
-The computational grid has one ghost layer in the radial and in the vertical direction . Periodic conditions are applied in the azimuthal direction. When running
+The computational grid has one ghost layer in the radial and in the vertical direction . Periodic conditions are applied in the azimuthal direction. The aim of boundary 
+condition is to assign values to the ghost layers for the whole set of hydro dynamical quantities.
+
+When running
 2D simulations only one boundary condition is required (radial)
 while for the 3D case it is necessary to provide a boundary condition also for the colatitude (to be applied to the set of gridcells having $`\phi =`$ Opening and $`\phi =\pi -`$ Opening). 
 When a 3D simulation is done by considering only one disk hemisphere (in case of vertical symmetry) a suited mirror boundary
 is automatically introduced at disk midplane. The vertical boundary condition will be then  applied only to the gridcells having $`\phi =`$ Opening. 
- The aim of boundary 
-condition is to provide a value for the whole set of hydrodynamical
-quantities into the ghost layers.
+ 
 Possible boundaries are: 
 1. ``open`` valid both for 2D and 3D disc. An open boundary will
 let the gas flowing out at the innermost and outermost radial