implement suggestions

Author: LasNikas

src/schemes/boundary/open_boundary/mirroring.jl

@@ -37,7 +37,9 @@ end
 """
     ZerothOrderMirroring()
 
-Fluid properties are interpolated onto ghost nodes using Shepard interpolation [Shepard1968](@cite).
+Fluid properties are interpolated onto ghost nodes using Shepard interpolation.
+(See slide 6 from the 4th DualSPHysics Users Workshop:
+[Tafuni, Lisbon 2018](https://dual.sphysics.org/4thusersworkshop/data/_uploaded/PDF_Talks_4thWorkshop/Tafuni_Lisbon2018.pdf)).
 The position of the ghost nodes is obtained by mirroring the boundary particles
 into the fluid along a direction that is normal to the open boundary.
 The interpolated values at the ghost nodes are then assigned to the corresponding boundary particles.

test/schemes/boundary/open_boundary/mirroring.jl

@@ -367,6 +367,10 @@
 
         pressure_func(pos) = cos(2pi * pos[1])
 
+
+        # The pressures are interpolated to obtain a unified vector of length 50,
+        # rather than handling three separate systems with numerous particles each.
+        # Additionally, it facilitates plotting for test validation purposes.
         pressures = interpolate_pressure.([
                                               SimpleMirroring(),
                                               FirstOrderMirroring(),