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 for courant numbers in Quickin

Roland Hesse, modified 5 Years ago.

Error for courant numbers in Quickin

Youngling Posts: 19 Join Date: 11/21/14 Recent Posts
Dear All,

I used the option to calculate and display the courant number in quickin (Operation Menu>Courant numbers). Basically the calculated values are reasonable (referring to the water depth), but at a few grid cells (top right boarder) there are strange values displayed. Does anyone know why this could happen? Might this only be due to the display/ interpolation problems in quickin?

kind regards,

Chloe Sarah Leach, modified 3 Months ago.

RE: Error for courant numbers in Quickin

Youngling Posts: 7 Join Date: 1/15/19 Recent Posts
Hi Roland,
Did you manage to resolve this issue? I have a similar issue where I'm getting extremely high localised courant numbers but there is nothing significant in the bathymetry that might be causing it, as far as I can see.
Thanks, Chloe