[examples][ff] Reorganise introduction

examples/freeflowchannel/.doc_config

@@ -2,7 +2,6 @@
     "README.md" : [
         "doc/intro.md",
         "problem.hh",
-        "main.cc",
-        "doc/results.md"
+        "main.cc"
     ]
 }

examples/freeflowchannel/README.md

 <!-- Important: This file has been automatically generated by generate_example_docs.py. Do not edit this file directly! -->
 
-This example is based on dumux/test/freeflow/navierstokes/channel/2d.
-
 # Freeflow through a channel
 
-## Problem set-up
-This example contains a stationary free flow of a fluid through two parallel solid plates in two dimensions from left to right. The figure below shows the simulation set-up. The fluid flows into the system at the left with a constant velocity of $` v = 1~\frac{\text{m}}{\text{s}} `$. The inflow velocity profile is a block profile. Due to the no-slip, no-flow boundary conditions at the top and bottom plate, the velocity profile gradually assumes a parabolic shape along the channel. At the outlet, the pressure is fixed and a zero velocity gradient in x-direction is assumed. The physical domain, which is modeled is the rectangular domain $`x\in[0,10],~y\in[0,1]`$.
+You learn how to:
+* solve a free flow channel problem
+* set outflow boundary conditions in the free-flow context
 
-![](./img/setup.png)
+__Results:__ In this example we will obtain the following stationary velocity profile:
+
+![](./img/velocity.png)
+
+## Folder layout and files
+
+```
+└── freeflowchannel/
+    ├── CMakeLists.txt          -> build system file
+    ├── main.cc                 -> main program flow
+    ├── params.input            -> runtime parameters
+    ├── properties.hh           -> compile time configuration
+    └── problem.hh              -> boundary & initial conditions
+```
 
-## Model description
+## Mathematical model
 The Stokes model without gravitation and without sources or sinks for a stationary, incompressible, laminar, single phase, one-component, isothermal ($`T=10^\circ C`$) flow is considered assuming a Newtonian fluid of constant density $` \varrho = 1~\frac{\text{kg}}{\text{m}^3} `$ and constant kinematic viscosity $` \nu = 1~\frac{\text{m}^2}{\text{s}} `$. The momentum balance
 ```math
 - \nabla\cdot\left(\mu\left(\nabla\boldsymbol{u}+\nabla\boldsymbol{u}^{\text{T}}\right)\right)+ \nabla p = 0
@@ -18,9 +30,16 @@ with density  $`\varrho`$, velocity $`\boldsymbol{u}`$, dynamic viscosity  $`\mu
 ```math
 \nabla \cdot \left(\varrho\boldsymbol{u}\right) =0
 ```
-are discretized using a staggered-grid finite-volume scheme as spatial discretization with pressures and velocity components as primary variables. For details on the discretization scheme, have a look at the dumux [handbook](https://dumux.org/handbook).
+are discretized using a staggered-grid finite-volume scheme as spatial discretization with pressures and velocity components as primary variables. For details on the discretization scheme, have a look at the Dumux [handbook](https://dumux.org/handbook).
 
-In the following, we take a close look at the files containing the set-up: At first, boundary conditions are set in `problem.hh` for the Navier-Stokes model. Afterwards, we show the different steps for solving the model in the source file `main.cc`. At the end, we show some simulation results.
+## Problem set-up
+This example contains a stationary free flow of a fluid through two parallel solid plates in two dimensions from left to right. The figure below shows the simulation set-up. The fluid flows into the system at the left with a constant velocity of $` v = 1~\frac{\text{m}}{\text{s}} `$. The inflow velocity profile is a block profile. Due to the no-slip, no-flow boundary conditions at the top and bottom plate, the velocity profile gradually assumes a parabolic shape along the channel. At the outlet, the pressure is fixed and a zero velocity gradient in x-direction is assumed. The physical domain, which is modeled is the rectangular domain $`x\in[0,10],~y\in[0,1]`$.
+
+![](./img/setup.png)
+
+In the following, we take a close look at the files containing the set-up: At first, boundary conditions are set in `problem.hh` for the Navier-Stokes model. Afterwards, we show the different steps for solving the model in the source file `main.cc`.
+
+# Implementation
 
 
 ## The file `problem.hh`
@@ -570,11 +589,3 @@ catch (...)
 </details>
 
 
-## Results
-This example computes the following stationary velocity profile:
-
-![](./img/velocity.png)
-
-and stationary pressure profile:
-
-![](./img/pressure.png)

examples/freeflowchannel/doc/intro.md

-This example is based on dumux/test/freeflow/navierstokes/channel/2d.
-
 # Freeflow through a channel
 
-## Problem set-up
-This example contains a stationary free flow of a fluid through two parallel solid plates in two dimensions from left to right. The figure below shows the simulation set-up. The fluid flows into the system at the left with a constant velocity of $` v = 1~\frac{\text{m}}{\text{s}} `$. The inflow velocity profile is a block profile. Due to the no-slip, no-flow boundary conditions at the top and bottom plate, the velocity profile gradually assumes a parabolic shape along the channel. At the outlet, the pressure is fixed and a zero velocity gradient in x-direction is assumed. The physical domain, which is modeled is the rectangular domain $`x\in[0,10],~y\in[0,1]`$.
+You learn how to:
+* solve a free flow channel problem
+* set outflow boundary conditions in the free-flow context
 
-![](./img/setup.png)
+__Results:__ In this example we will obtain the following stationary velocity profile:
 
-## Model description
+![](./img/velocity.png)
+
+## Folder layout and files
+
+```
+└── freeflowchannel/
+    ├── CMakeLists.txt          -> build system file
+    ├── main.cc                 -> main program flow
+    ├── params.input            -> runtime parameters
+    ├── properties.hh           -> compile time configuration
+    └── problem.hh              -> boundary & initial conditions
+```
+
+## Mathematical model
 The Stokes model without gravitation and without sources or sinks for a stationary, incompressible, laminar, single phase, one-component, isothermal ($`T=10^\circ C`$) flow is considered assuming a Newtonian fluid of constant density $` \varrho = 1~\frac{\text{kg}}{\text{m}^3} `$ and constant kinematic viscosity $` \nu = 1~\frac{\text{m}^2}{\text{s}} `$. The momentum balance
 ```math
 - \nabla\cdot\left(\mu\left(\nabla\boldsymbol{u}+\nabla\boldsymbol{u}^{\text{T}}\right)\right)+ \nabla p = 0
@@ -16,6 +28,13 @@ with density  $`\varrho`$, velocity $`\boldsymbol{u}`$, dynamic viscosity  $`\mu
 ```math
 \nabla \cdot \left(\varrho\boldsymbol{u}\right) =0
 ```
-are discretized using a staggered-grid finite-volume scheme as spatial discretization with pressures and velocity components as primary variables. For details on the discretization scheme, have a look at the dumux [handbook](https://dumux.org/handbook).
+are discretized using a staggered-grid finite-volume scheme as spatial discretization with pressures and velocity components as primary variables. For details on the discretization scheme, have a look at the Dumux [handbook](https://dumux.org/handbook).
+
+## Problem set-up
+This example contains a stationary free flow of a fluid through two parallel solid plates in two dimensions from left to right. The figure below shows the simulation set-up. The fluid flows into the system at the left with a constant velocity of $` v = 1~\frac{\text{m}}{\text{s}} `$. The inflow velocity profile is a block profile. Due to the no-slip, no-flow boundary conditions at the top and bottom plate, the velocity profile gradually assumes a parabolic shape along the channel. At the outlet, the pressure is fixed and a zero velocity gradient in x-direction is assumed. The physical domain, which is modeled is the rectangular domain $`x\in[0,10],~y\in[0,1]`$.
+
+![](./img/setup.png)
+
+In the following, we take a close look at the files containing the set-up: At first, boundary conditions are set in `problem.hh` for the Navier-Stokes model. Afterwards, we show the different steps for solving the model in the source file `main.cc`.
 
-In the following, we take a close look at the files containing the set-up: At first, boundary conditions are set in `problem.hh` for the Navier-Stokes model. Afterwards, we show the different steps for solving the model in the source file `main.cc`. At the end, we show some simulation results.
+# Implementation

examples/freeflowchannel/doc/results.md

-## Results
-This example computes the following stationary velocity profile:
-
-![](./img/velocity.png)
-
-and stationary pressure profile:
-
-![](./img/pressure.png)