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

time-varying wave boundary conditions with bcw file for coupled flow+wave

Kevin Hanegan, modified 1 Year ago.

time-varying wave boundary conditions with bcw file for coupled flow+wave

Youngling Posts: 6 Join Date: 7/2/11 Recent Posts


In a coupled flow+wave simulations, I'm trying to apply spatially-constant but time-varying wave BC's with the .bcw file method. My production runs will have too many timepoints to use the wavecon approach. The simulation runs fine when constant wave boundaries are specified. When defining a TseriesFiles and Timepoints in the .mdw file, the wave boundary conditions from the .bcw file are not being passed correctly to SWAN. Instead, NaN values (-999.00) are given fro all parameters in the swan.inp file (see attached). Note that the fine flow and wave grid is nested into a larger, coarse grid for the wave calcs. Are there any limitations to this method that I'm potentially violating? Does anyone see any issues with my setup? I've attached my .mdw and .bcw files. 

Thank you,