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

Keyword Filbal HELP

Alfonso M JR, modified 4 Years ago.

Keyword Filbal HELP

Youngling Posts: 8 Join Date: 1/22/14 Recent Posts
Hello everyone,

I am trying to compute a sediment mass balance inside a shallow bay system with Delft3D Flow. I've read that it can be done in an accurate way with the Keyword Filebal, however I am not able to understand the output results once the simulation finishes. Please, do you where I can get information about the outputs when the keyword Filebal is activated? Has someone used 'Filebal' previosly for doing a mass balance?

Thank you in advance !

alfonso m
Adri Mourits, modified 4 Years ago.

RE: Keyword Filbal HELP

Yoda Posts: 1221 Join Date: 1/3/11 Recent Posts
Hi Alfonso,

If the mdf file contains the line:
Filbal= #f34.pol#
(yes, it's filbal, not filebal), the file f34.pol should contain disjunct, named polygons. Then mass balance information is written to the output for the polygons and the area not being covered by the polygons.

Attached is a zip-file containing the input of a testcase.