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


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SWAN Wind Timeseries format.

Ed Atkin, modified 8 Years ago.

SWAN Wind Timeseries format.

Padawan Posts: 27 Join Date: 3/27/12 Recent Posts
This regards SWAN, not in its Delft3D incarnation.
I have a long time series (~8 years.). I have x and y values, from GFS, for wind on the edge of my model domain which I wish to apply across the entire grid ie. a constant value over the computational field foe each time step.
The data is in 3 hourly steps, to create individual files of x/y wind for each time step would result in more than 22,000 files.
I’m pretty sure I shouldn’t have to mirror a grid anyway for a constant value and an array of values should be sufficient (i.e. x1y1x2y2x3y3x4y4 etc.).
However when I run this and extract from a single point inside the model domain I have the same values for x and y vectors for every single time stamp.

So the question is, how should a time series such as this be formatted to be used in SWAN. (I have read the SWAN use manual over and over again and I still can’t figure it out)


I have successfully fun with mirrored grids for x and y values of wind alternatley listed in a single file. The size fo the file is around 2.5 gb. Something tells me this is completey correct.
Any suggestions welcome.