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

Where i can find a manual about using ice module?

Mitya Menshikov, modified 2 Years ago.

Where i can find a manual about using ice module?

Youngling Posts: 5 Join Date: 9/15/15 Recent Posts
Hello everyone.

I have downloaded Delft3D with ice-module from and successfully compiled it. So where i can find a manual about using this module?
Erik de Goede, modified 2 Years ago.

RE: Where i can find a manual about using ice module? (Answer)

Youngling Posts: 13 Join Date: 1/7/11 Recent Posts
Dear Mitya,

Thanks for your interest in our Delft3D ice module! There is no manual for modelling ice in Delft3D-FLOW, but it is quite simple. The extra keywords for ice read:
Ice = #Deltares#
(NB. There is also another ice model, but you should use this keyword so that the Deltares’ ice model is switched on.)

The snow fall is modelled via
Fileva = #input.eva#
(If the air temperature in the *.tem file is below zero, then it is assumed that the rain fall is in the form of snow)

Only the MAP file (and not the HIS-file) contains ice output: ice thickness, snow thickness ice concentration (i.e. fraction of a computational cell that is filled with ice) and the U-velocity of ice and the V-velocity of ice. Noted that the U- and V- ice velocities can only be visualized separately yet (thus no as vectors).

The horizontal transport of ice and snow can be switched on or off, via
Dynice = #N#
The latter saves computation time.

If you provide me with your e-mail address (by e-mailing to, then I will send you a few example models.

With kind regards,

Erik de Goede