Add PSM version of fluidized bed app

apps/showcases/FluidizedBed/CMakeLists.txt

 waLBerla_link_files_to_builddir( "*.prm" )
 
-waLBerla_add_executable ( NAME FluidizedBed FILES FluidizedBed.cpp
-                          DEPENDS blockforest boundary core domain_decomposition field lbm lbm_mesapd_coupling mesa_pd postprocessing timeloop vtk )
+waLBerla_add_executable ( NAME FluidizedBedMEM FILES FluidizedBedMEM.cpp
+                          DEPENDS blockforest boundary core domain_decomposition field lbm lbm_mesapd_coupling mesa_pd timeloop vtk )
+
+waLBerla_add_executable ( NAME FluidizedBedPSM FILES FluidizedBedPSM.cpp
+        DEPENDS blockforest boundary core domain_decomposition field lbm lbm_mesapd_coupling mesa_pd timeloop vtk )

src/lbm_mesapd_coupling/partially_saturated_cells_method/ParticleAndVolumeFractionMapping.h

@@ -77,6 +77,22 @@ class ParticleAndVolumeFractionMapping
       {
          if (mappingParticleSelector_(idx, *ac_)) { update(idx); }
       }
+
+      // normalize the sum of all overlap fractions of a cell to 1
+      for (auto blockIt = blockStorage_->begin(); blockIt != blockStorage_->end(); ++blockIt)
+      {
+         ParticleAndVolumeFractionField_T* particleAndVolumeFractionField =
+            blockIt->getData< ParticleAndVolumeFractionField_T >(particleAndVolumeFractionFieldID_);
+
+         WALBERLA_FOR_ALL_CELLS_XYZ(
+            particleAndVolumeFractionField, real_t fractionSum = 0.0;
+            for (auto& e
+                 : particleAndVolumeFractionField->get(x, y, z)) fractionSum += e.second;
+            if (fractionSum > 1.0) {
+               for (auto& e : particleAndVolumeFractionField->get(x, y, z))
+                  e.second /= fractionSum;
+            })
+      }
    }
 
  private: