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 to change breaker delay (F_lam) parameter?

Sarah Margaret Trimble, modified 1 Year ago.

Where to change breaker delay (F_lam) parameter?

Youngling Posts: 3 Join Date: 5/24/18 Recent Posts


We are thinking of doing a sensitivity analysis of the parameters for our study site, following a similar process to Giardino, Brière, & van der Werf (2010). One parameter they discuss (that we are also interested in) is a "breaker delay" parameter that I think is set by the keyword F_lam in the wave input files. However, I cannot find either "breaker delay" or the keyword F_lam in the manuals for FLOW or WAVE (written in 2013).

Does anyone know: where and how is this parameter set in the most recent tag version of Delft3D? Any hints or educated guesses are welcome!



Sarah T