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

Delft3D different versions compatibility

Hanieh Mohamadi Moghadam, modified 2 Years ago.

Delft3D different versions compatibility

Youngling Posts: 4 Join Date: 8/20/17 Recent Posts

Dear Delft3D users,

I'm using Delft3D 4.03.00 and 4.01.00 on two different computers (Windows).

When I open the 4.03 version flow input file (.mdf) with the 4.01 version, the model gives a warning "This file is created by a newer version of FLOW GUI. This may lead to unexpected behaviour". I neglect the warning and run the model on the older version. It gives the following error:

"At least 2 observation points must be defined when writing to history file"

I added a .obs file and it runs successfully!

However I could run the same model on 4.03 version without any observation point!

Is it the difference between these two versions' flow input files?

Is there any other difference that I should be aware of?