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

Culverts in parallel

Richard Measures, modified 7 Years ago.

Culverts in parallel

Jedi Knight Posts: 178 Join Date: 3/23/11 Recent Posts

I have a coastal model with several culverts in and it would be very useful to be able to run it parallel but I note that on parallel_status.txt culverts are listed as not supported for parallel running.

Are there any plans to remove this limitation in the near future? What is the current issue in the code that is preventing culverts from running in parallel - perhaps if you can point me in the right direction I may be able to develop the code to remove this limitation?


Adri Mourits, modified 7 Years ago.

RE: Culverts in parallel

Yoda Posts: 1221 Join Date: 1/3/11 Recent Posts
Hi Richard,

To handle culverts with intake point and outfall point inside the same partition:
  • Be sure that culverts that don't lie completely inside the current partition are removed
  • Be sure that all culverts have the correct local indices instead of the global indices

To enable the general case (two-way culverts with intake/outfall point in different partitions):
  • Be sure that culverts that don't lie completely inside the current partition are not removed/disabled
  • Be sure that all culverts have the correct local indices instead of the global indices
  • Add an array for "all needed quantities" related to the intake points. These quantities differ for each type of culvert.
  • Fill this array for all intake points inside the current partition.
  • Exchange this array between all partitions
  • Compute "all needed quantities" related to the outfall points inside the current partition.
  • Compute the discharge of each culvert
  • Swap intake and outfall points when needed
  • Exchange discharges and swap-info between all partitions
  • Be sure that the rest of the program can handle culverts with intake and/or outfall point outside this partition