intro story D-Flow FM


D-Flow Flexible Mesh

D-Flow Flexible Mesh (D-Flow FM) is the new software engine for hydrodynamical simulations on unstructured grids in 1D-2D-3D. Together with the familiar curvilinear meshes from Delft3D 4, the unstructured grid can consist of triangles, pentagons (etc.) and 1D channel networks, all in one single mesh. It combines proven technology from the hydrodynamic engines of Delft3D 4 and SOBEK 2 and adds flexible administration, resulting in:

  • Easier 1D-2D-3D model coupling, intuitive setup of boundary conditions and meteorological forcings (amongst others).
  • More flexible 2D gridding in delta regions, river junctions, harbours, intertidal flats and more.
  • High performance by smart use of multicore architectures, and grid computing clusters.
An overview of the current developments can be found here.
The D-Flow FM - team would be delighted if you would participate in discussions on the generation of meshes, the specification of boundary conditions, the running of computations, and all kinds of other relevant topics. Feel free to share your smart questions and/or brilliant solutions! 


We have launched a new website (still under construction so expect continuous improvements) and a new forum dedicated to Delft3D Flexible Mesh.

Please follow this link to the new forum: 

Post your questions, issues, suggestions, difficulties related to our Delft3D Flexible Mesh Suite on the new forum.





Sub groups
D-Flow Flexible Mesh
Cohesive sediments & muddy systems


Message Boards

Sand-mud interaction

Michael Streßer, modified 6 Years ago.

Sand-mud interaction

Youngling Posts: 1 Join Date: 8/4/14 Recent Posts
Hello everybody!

I'm trying to model long time moprhodynamics in a muddy area in the east frisian wadden sea in Germany.
As I read in the release notes, since delft3d version the sand-mud interaction from the build with nature project is implemented. I'm using and unluckily I'm not able to switch it on.
I've tried it as follows:
1.: Add PmCrit = 0.3 and Betam = 3 to the *.mdf file as originally suggested here
2.: Add PmCrit = 0.3 and Betam = 3 to the *.sed file in the SedimentOverall-block ( that's where I believe it should be after I checked the import routines in the source code)

Both ways lead to the line "Sand mud interaction with crit: -0.1000E+01" in the tri-diag file, which means that sand mud interaction is not taken into account.

Do you have any suggestions how to solve this?

Thanks for your comments,
Julia Vroom, modified 4 Years ago.

RE: Sand-mud interaction

Youngling Posts: 1 Join Date: 7/20/16 Recent Posts
Hi Micha,

You should indeed add the keywords to the *.sed file (like to describe in option 2). For me the sand-mud interaction seems to work with Delft3D version

Good luck!