[staggerednc][test] Fix tests and update ref solution

* Old test used parabolic velocity profile as initital and boundary condition
  although Re was way over 1000. This led to some strange behaviour regarding
  the pressure gradient

* We now give the system some additional time so that the "right" pressure gradient
  can evolve before injecting the tracer

* Add output of deltaP

test/freeflow/staggerednc/CMakeLists.txt

@@ -19,7 +19,7 @@ add_dumux_test(test_advection test_channel test_channel.cc
                python ${CMAKE_SOURCE_DIR}/bin/testing/runtest.py
                  --script fuzzy
                  --files ${CMAKE_SOURCE_DIR}/test/references/stokes2c-advection.vtu
-                         ${CMAKE_CURRENT_BINARY_DIR}/test_advection-00002.vtu
+                         ${CMAKE_CURRENT_BINARY_DIR}/test_advection-00009.vtu
                  --command "${CMAKE_CURRENT_BINARY_DIR}/test_channel test_advection.input")
 
 

test/freeflow/staggerednc/channeltestproblem.hh

@@ -239,7 +239,10 @@ public:
     {
         BoundaryValues values = initialAtPos(globalPos);
 
-        if(isInlet(globalPos))
+        const Scalar time = this->timeManager().time() + this->timeManager().timeStepSize();
+
+        // give the system some time so that the pressure can equilibrate, then start the injection of the tracer
+        if(isInlet(globalPos) && time > 20.0)
             values[transportCompIdx] = 1e-3;
 
         return values;
@@ -272,6 +275,30 @@ public:
         return values;
     }
 
+    /*!
+     * \brief Adds additional VTK output data to the VTKWriter. Function is called by the output module on every write.
+     */
+    template<class VtkOutputModule>
+    void addVtkOutputFields(VtkOutputModule& outputModule) const
+    {
+        auto& deltaP = outputModule.createScalarField("deltaP", 0);
+
+        for (const auto& element : elements(this->gridView()))
+        {
+            auto fvGeometry = localView(this->model().globalFvGeometry());
+            fvGeometry.bindElement(element);
+            for (auto&& scv : scvs(fvGeometry))
+            {
+                auto ccDofIdx = scv.dofIndex();
+
+                auto elemVolVars = localView(this->model().curGlobalVolVars());
+                elemVolVars.bind(element, fvGeometry, this->model().curSol());
+
+                deltaP[ccDofIdx] = elemVolVars[scv].pressure() - 1.1e5;
+            }
+        }
+    }
+
     // \}
 
 private:

test/freeflow/staggerednc/test_advection.input

 [TimeManager]
-DtInitial = 5e-3 # [s]
-TEnd = 1e-2 # [s]
+DtInitial = 5 # [s]
+TEnd = 400 # [s]
 
 [Grid]
 UpperRight = 5 1
@@ -8,7 +8,7 @@ Cells = 50 25
 
 [Problem]
 Name = test_advection # name passed to the output routines
-InletVelocity = 1000
+InletVelocity = 1e-2
 EnableGravity = false
 
 [ Newton ]

test/references/stokes2c-purediffusion.vtu

@@ -482,6 +482,50 @@
           0 0 0 0 0 0 0 0 0 0 0 0
           0 0 0 0 0 0 0 0
         </DataArray>
+        <DataArray type="Float32" Name="deltaP" NumberOfComponents="1" format="ascii">
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0 0 0 0 0
+          0 0 0 0 0 0 0 0
+        </DataArray>
       </CellData>
       <Points>
         <DataArray type="Float32" Name="Coordinates" NumberOfComponents="3" format="ascii">