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

Filbal keyword and Linux

Jessica Chassereau, modified 8 Years ago.

Filbal keyword and Linux

Youngling Posts: 15 Join Date: 4/21/11 Recent Posts

I am would like to use the Filbal keyword to add a series of polygons through which water balance is monitored. I was successful in running the Filbal simulation on a single processor and would like to run the same simulation on our linux cluster to improve computation time. However, when I attempt to run the job on the linux cluster, I get the following error:

Nefis error:
NEFIS message 5014:
Group 'his-bal-series ' already exists on file 'trih-gr1.def'.
While trying to define group his-bal-series in file trih-gr1.def

ERROR: d_hydro.exe: gp.c:140: FileSeek: Assertion `retVal != -1' failed.
- Starting "d_hydro.exe" may give more information:
- Run "deltares_hydro.exe <INI-inputfile> -keepXML".
- Run "d_hydro.exe TMP_config_flow2d3d_<processId>.xml".

Have any of you encountered this problem? If so, how might the issue be resolved?