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

Domain Decomposition

Phil Shepperd, modified 4 Years ago.

Domain Decomposition

Padawan Posts: 33 Join Date: 5/31/11 Recent Posts
Hi all. I'm having a problem with a 4 grid DD model, in that when I make a tiny change to the inner grid - e.g. adding a thin dam - the changes in velocities through all grids (except the outer one) are far larger than can be attributed to the change. The changes are seemingly starting at the grid interfaces, so I wonder whether it is to do with the way bathymetry has been defined. Values at common points are the same. From the Quickin manual: "Furthermore, for the re ned model, it is proposed that the depth values in the intermediate points are determined by linear interpolation." To do this manually in Quickin would take a very long time. Does it offer another way? Is there another possible explanation for what I'm seeing? Thank you
João Lencart e Silva, modified 4 Years ago.

RE: Domain Decomposition

Padawan Posts: 71 Join Date: 3/30/11 Recent Posts
Hi Phil,

A late response to this...

Have you tried using the matlab tools to interpolate between the common grid points in the interface?
Alternatively you can use the openearth tools to load your dep file into python and use numpy for the interpolation:

Hope it helps,