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

Staircasing when creating grid

Akash Melethil, modified 5 Years ago.

Staircasing when creating grid

Padawan Posts: 26 Join Date: 5/13/14 Recent Posts
Are there any documentation about how the computation is done when using staircasing during grid creation. I have found information on the topic of staircasing in relation to the Z-grid in the manual, but it does not talk about how it works in the x-y grid.
Jan Mooiman, modified 5 Years ago.

RE: Staircasing when creating grid

Youngling Posts: 14 Join Date: 1/7/11 Recent Posts
Dear Akash,

For the sigma-model no special implementation is made for a stair-case boundary in the x-y-plane, where it is for the Z-model (cut-cell method).
Because the algorithms between a sigma-model and a Z-model are different, a one layer model defined as sigma-model does not have the cut-cell method where a Z-modal has.

Regards Jan Mooiman