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

Space-varying non-Starionary spectral files

Joao Morim do Nascimento, modified 7 Years ago.

Space-varying non-Starionary spectral files

Youngling Posts: 13 Join Date: 3/8/13 Recent Posts
Hello community,

I have seen in SWAN and DELFT3D manual how to define spectral files in order to force our boundary conditions. However, it not mentioned anywhere how to define a 2D space varying non stationary spectral file. There is an example of a 1D nonstationary spherical coordinates file (but it appears that gives the same values for both locations) and there is an example of a 2D stationary Cartesian coordinates file (which obviously do not consider time).

I am trying to build a file that considers several locations and each location varies in time. Does anyone known what is the file structure?

Arjen Luijendijk, modified 7 Years ago.

RE: Space-varying non-Starionary spectral files

Padawan Posts: 38 Join Date: 2/22/11 Recent Posts
I suggest that you follow the same way as the 1D spherical spectrum file with time stamp. Simply replace the 1D with a 2D spectrum. You can add different spectra (with different locations and time stamps) in one file. See the SWAN manual for example.
If you select this sp2 file in the mdw file this will work correctly. If you want to apply spectra files for each specified segment or boundary, keep in mind that you can not refer to the same spectrum file multiple times. SWAN does not accept this; so, make sure the file names are different per segment or boundary.

Good luck, Arjen