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

non-hydrostatic z-level and parallel

Markus Gross, modified 4 Years ago.

non-hydrostatic z-level and parallel

Youngling Posts: 7 Join Date: 12/10/11 Recent Posts

I am setting up a non-hydrostatic z-level model. It is running fine in serial, but needs 180days to run for three days emoticon

Therefore I would obviously like to run in parallel, but whilst it runs there is a clear sign of CPU boundaries imprinting and, depending on the revision number setting Nharea may or may not work. In the latest revisions I found it does not, because it compares the limits to the local grid numbering, not the global one. For rev. 6680 it "works" but I have not looked at the result yet, I guess it is not right (hence the change in the later revisions).

Therefore my question: It seems that it is ongoing work to get the z-level (non-hydro) to work in parallel, correct? If yes, is there any estimate when that should be working? I.e. is it a priority for deltares or not? If yes I would obviously not "waste" my time tying to get it to work, just to find that a month later you have done it properly. If not then I may be tempted to see what I can do.

Many thanks!
Best wishes,
Adri Mourits, modified 4 Years ago.

RE: non-hydrostatic z-level and parallel (Answer)

Yoda Posts: 1221 Join Date: 1/3/11 Recent Posts
Hi Markus,

Parallellization of the non-hydrostatic z-level model is currently not having a high priority. You are free to have a go at it. Please let me know if you want a branch in subversion or if you have questions.