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

ERROR closing file. NetCDF file : "". Error message:Unknown error

Aspen M M Anderson, modified 4 Months ago.

ERROR closing file. NetCDF file : "". Error message:Unknown error

Youngling Posts: 3 Join Date: 8/5/18 Recent Posts

I am having issues exporting my model outputs in NetCDF format. The model runs to completion when I am export the output to a .dat file, so I know nothing is wrong with the model itself. When I add the flag "FINcdf = #map#" to the .mdf file the model crashes around 21% completion and gives the error "ERROR closing file. NetCDF file : "". Error message:Unknown error" in the tri-diag file. The iteration the model crashes on changes every time I rerun the model, but usually crashes around 20%. A .nc output file is produced with someone of the results, I am just not sure why the model isn't running to completion. Any insight on how to successfully export my model outputs to NetCDF format is greatly appreciated!


Francisco Rafael Xavier, modified 1 Month ago.

RE: ERROR closing file. NetCDF file : "". Error message:Unknown err

Youngling Posts: 1 Join Date: 8/24/17 Recent Posts
Hi Aspen,

I had this error in my simulation and solved it by adding the output 'Addtim' #YES#, 'FINcdf' #map his # and not choosing compilation mode. When I put only #map# the simulation crashs and shows the message: "ERROR closing file. NetCDF file : "--". Error message:Unknown error"


Francisco Rafael