User manual

User manual for CFD-DEM simulation

Examples & tutorials

Some preliminary examples are located under directory examples/, which can be run with, e.g., (in the example directory)

    ./Allrun

Note if the pynetdem package cannot be imported into python, one might need to exiplictly add the path (e.g., sys.path.append("/Users/lzhshou/Documents/Research/myProjects/apaam/repo/netdem/build/lib/")) of the netdem python library in createDEM.py.

Run water entry example

  • Copy the example folder to a local directory

    cd cfddem
cp -rf examples/interIBdem/water_entry local/interIBdem/

  • Run the example

    • Please note that system/fvSolution -> coupling specifies the DEM file and function that will be invoked for the coupling.
      cd local/interIBdem/water_entry
./Allclean
./Allrun-parallel

  • In case the run fails, please check the lib path has been correctly set in createDEM.py, where the path is the directory of netdem libs.

Paraview Rendering

  • Render CFD results

    • Open interIBdem.foam to paraview
    • Change the properties Type Case to Decomposed Case and uncheck Skip Zero Time (optional)
    • Play with the result fields
    • Optinal: for viaulizeing interal filed results, one can use the Clip or Slice filter
    • Optinal: to construct the interface of the water and air, one can add Contour filter to interIBdem.foam, set Contour by to alpha.water and change the contour value to 0.5

  • Render DEM results

    • Open dem/particle_mesh_xxx.vtk.serries to paraview
    • Optional: select all particle_mesh_xxx.vtk.serries and add a Group Datesets filter
    • Optional: add a Caculator filter after the Group Datesets filter, set Result Array Name to U, and input formulation vel. This will add a U field to the particles, wihch can be linked with the CFD field U
    • Optional: for probing the evolution of a property value with time, one can add a Plot Data Over Time filter to the Group Datesets, and change the Field Associates to Cells. Then, one can play with the property to show in the newly opened Line Chart View

Modify the water entry parameters

  • Fuild properties such as viscosity and density is specified in file constant/transportProperties.
    • Please note that fuilds being used are speficied in phases.
  • Geometries are determined by the system/blockMeshDict. Please note that when scale exist, the coordinates of the vertices with be multiplied by the scale when creating the real mesh.
    • Mesh size are govened by the three values before simpleGrading in the blocks -> hex entry. It is suggested to use cubic elements.
  • The inital volume fraction of the fuilds are specifed in system/setFiledsDict.
    • Please not that the scale parameter in system/blockMeshDict will not work here, thus the vertices here are their exact values.
    • Entry box (-0.05 -0.05 -0.15) (0.05 0.05 0.03) specifies the lower-left-front and upper-right-back coordicates of the box
    • Please note that the field entry alpha.glycerol should be consistent with that specified in constant/transportProperties -> phases
  • File system/controlDict specifies the simulation time, timestep and writing interval, etc.
  • In createDEM.py -> oneSphere() funciton, one can modify the DEM domain geometries and particle properties.
    • Please note that in the present funciton, the parameter scale varies the size of the DEM domain, wall box and particle intertion region, whereas the p_size is the exact value of particle diameter.

User manual