Merge branch 'cleanup/ff-pm-ex' into 'master'

[ex][ff-pm] cleanup readme and ex

See merge request !282

exercises/exercise-coupling-ff-pm/README.md

@@ -101,10 +101,10 @@ mass and momentum fluxes coming from the porous domain and uses these values as
         return values;
     }
 ```
-Note that certain checks are performed when combining different models, e.g., the fluid system has to be the same for both domains
+> Note: Certain checks are performed when combining different models, e.g., the fluid system has to be the same for both domains
 and the sub-control-volume faces at the interface have to match.
-
-We will use a staggered grid (also calles Marker-and-Cell method - MAC) to discretize the free-flow domain and a cell-centered finite volume (CCFV) method for the porous medium domain.
+>
+We will use a staggered grid (also called Marker-and-Cell method - MAC) to discretize the free-flow domain and a cell-centered finite volume (CCFV) method for the porous medium domain.
 Keep in mind that the staggered grid implementation distinguishes between face variables (velocity components) and cell center variables (all other variables).
 For this reason one distinguishes between `CouplingManager::stokesCellCenterIdx` and `CouplingManager::stokesFaceIdx` indices (see `main.cc`), while for the porous medium all variables can be accessed with `CouplingManager::darcyIdx`.
 

exercises/exercise-coupling-ff-pm/interface/README.md

@@ -60,9 +60,12 @@ if(onRightBoundary_(globalPos))
     values[Indices::pressureIdx] = 0.0;
 ```
 
-For changing the flow direction, the boundary conditions for the porous medium have to be changed as well.
+This should make the flow go from left to right.
+If not already done, you can also delete the vertical velocity from `dirichletAtPos`, as Dirichlet-type boundary conditions should be set for the pressure.
+
+For changing the flow direction, the boundary conditions for the porous medium (in `interface/porousmediumsubproblem.hh`) have to be changed as well.
 
-Use Neumann no-flow boundaries everywhere, keep the coupling conditions.
+Use Neumann no-flow boundaries everywhere and keep the coupling conditions.
 ``` cpp
 values.setAllNeumann();
 
@@ -70,9 +73,6 @@ if (couplingManager().isCoupledEntity(CouplingManager::darcyIdx, scvf))
     values.setAllCouplingNeumann();
 ```
 
-This should make the flow go from left to right.
-You can also delete the vertical velocity from `dirichletAtPos`, as Dirichlet-type boundary conditions should be set for the pressure.
-
 Recompile and rerun your code. Then check your results with the applied changes by visualizing them e.g. with paraview.
 
 ### Task B: Include slip-condition
@@ -105,6 +105,8 @@ freeflowVtkWriter.addField(freeflowProblem->getAnalyticalVelocityX(), "analytica
 After re-compiling and re-running the executable, we should be able to see also
 the analytical solution of $`v_x`$ on the free flow domain. Play around with the grid resolution in the input file to see how that affects the resulting velocity profile.
 
+> Note: In Paraview you can e.g. use the tool `PlotOverLine` to plot the velocity in $x$-direction ($v_x$) over the y-Axis (e.g. at the outlet or the middle of the domain). After choosing `PlotOverLine` make sure to give the Point 1 and the Point 2 to define the line or click on the button `Y Axis` and check the coordinates of the points. Click on `Apply` and in section `Series Parameters` choose to only visualize `velocity_gas(m/s)_X` and `analyticalV_x`.
+
 ### Task C: Change the shape of interface
 
 Now we want to include a non-flat interface between the two domains.
@@ -139,6 +141,10 @@ Make sure that you have uncommented the line for including the grid manager in t
 
 and do the changes in the respective lines for the `Grid` property.
 
+As well we have to define the parameters only for the base grid if using `dune-subgrid`. For this uncomment the block `[Grid]` in `interface/params.input` and comment the groups `[Freeflow.Grid]` and `[PorousMedium.Grid]`. 
+
+>Note: The four additional parameters `Baseline`, `Amplitude`, `Offset` and `Scaling` define the sinus-shaped interface in the main-file (the block you previously uncommented).
+
 The problem should now compile. However, a runtime error occurs due to the coupling conditions.
 So far, we assumed a flat interface, therefore the normal momentum coupling condition
 

exercises/exercise-coupling-ff-pm/interface/params.input

-# for dune-subgrid
-[Grid]
-Positions0 = 0 1
-Positions1 = 0 0.2 0.3 0.65
-Cells0 = 100
-Cells1 = 10 50 18
-Baseline = 0.25 # [m]
-Amplitude = 0.04 # [m]
-Offset = 0.5 # [m]
-Scaling = 0.2 #[m]
+# # TODO: dumux-course-task 1.C: uncomment the following group [Grid]
+# # for dune-subgrid
+#[Grid]
+#Positions0 = 0 1
+#Positions1 = 0 0.2 0.3 0.65
+#Cells0 = 100
+#Cells1 = 10 50 18
+#Baseline = 0.25 # [m]
+#Amplitude = 0.04 # [m]
+#Offset = 0.5 # [m]
+#Scaling = 0.2 #[m]
 
+# TODO: dumux-course-task 1.C: comment or delete the group [Freeflow.Grid]
 [Freeflow.Grid]
 Verbosity = true
 Positions0 = 0.0 1.0
@@ -17,6 +19,7 @@ Cells0 = 20
 Cells1 = 100
 Grading1 = 1
 
+# TODO: dumux-course-task 1.C: comment or delete the group [PorousMedium.Grid]
 [PorousMedium.Grid]
 Verbosity = true
 Positions0 = 0.0 1.0
@@ -25,6 +28,10 @@ Cells0 = 20
 Cells1 = 20
 Grading1 = 1
 
+[Problem]
+Name = ex_ff-pm-interface
+EnableGravity = false
+
 [Freeflow.Problem]
 Name = freeflow
 PressureDifference = 1e-9
@@ -39,9 +46,5 @@ Porosity = 0.4
 AlphaBeaversJoseph = 1.0
 Temperature = 283.15
 
-[Problem]
-Name = ex_ff-pm-interface
-EnableGravity = false
-
 [Vtk]
 AddVelocity = 1

exercises/solution/exercise-coupling-ff-pm/interface/params.input

@@ -25,6 +25,10 @@ Cells0 = 20
 Cells1 = 20
 Grading1 = 1
 
+[Problem]
+Name = ex_ff-pm-interface
+EnableGravity = false
+
 [Freeflow.Problem]
 Name = freeflow
 PressureDifference = 1e-9
@@ -39,9 +43,5 @@ Porosity = 0.4
 AlphaBeaversJoseph = 1.0
 Temperature = 283.15
 
-[Problem]
-Name = ex_ff-pm-interface
-EnableGravity = false
-
 [Vtk]
 AddVelocity = 1