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

Wrong results obtained using SWAN when taking diffraction into account

Peng Dai, modified 9 Months ago.

Wrong results obtained using SWAN when taking diffraction into account

Padawan Posts: 59 Join Date: 8/2/12 Recent Posts

Dear all:

I came to  an obviously wrong results when simulating waves using SWAN. It's a course domain and fine domain coupled simulation. When I uncheck the diffraction effect, everything seems all right (pls see the figure 1&2 attached). However when the diffraction is taken into account, the result for the fine domain is zero wave height(pls see the attached figure 4), no waves, which is not reasonable. Please note that the results for the course domain is OK (pls see the attched figure 3).


Can you kindly give me some advice? These figures are numbered in a sequential manner. The log file is also attached. let me know if you would like more information about.