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

NEFIS error

Serene Tay, modified 9 Years ago.

NEFIS error


I am using a 64bit Delft3D-FLOW version: Deltares, FLOW2D3D Version, Dec 27 2011, 20:21:08, compiled with Intel Compiler 12. However I encountered the following NEFIS error in the middle of my simulation;

NEFIS message 8025:
Unable to close data file 'trih-ps16g_test.dat'

May someone tell me how can I resolve this?

Serene Tay
Bert Jagers, modified 9 Years ago.

RE: NEFIS error

Jedi Knight Posts: 201 Join Date: 12/22/10 Recent Posts
Hi Serene,

Since you refer to a 64bit version, I assume that you are running Linux.

Unfortunately, the version number alone does not indicate which source code you are compiling. Did you compile the trunk or a tagged version?
If you're using one of the tagged versions, please try for 64bit Linux the trunk version.

You have compiled a version based on revision 1089. Adri Mourits made several modifications to the trunk after that revision. I recommend to update the source code to include all changes that Adri made afterwards; I haven't heard from Adri about this particular problem before he left for Christmas holidays, but it's always good to include his latest changes.

Please test if after these changes the problem still persists. I have encountered on a 64bit Linux system a similar error: the simulation ran fine until it crashed upon closing a NEFIS file; it didn't give this NEFIS message. Unfortunately, I haven't had the time to dig into that problem and currently both our main Delft3D Linux developer and the NEFIS developer are on holidays.