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

part module - chess board pattern tracer concentration

Hailiang Shen, modified 5 Years ago.

part module - chess board pattern tracer concentration

Youngling Posts: 10 Join Date: 2/14/12 Recent Posts
I am modelling oil spill for a river section with D-Part. I am only modelling instantaneous release, and get a chess board pattern for tracer concentration as seen attached.

To me it does not make sense. Can anyone help to answer why the concentration is not continuous in space? Thanks

Qinghua Ye, modified 5 Years ago.

RE: part module - chess board pattern tracer concentration

Jedi Council Member Posts: 612 Join Date: 3/2/11 Recent Posts
Hi Hailiang,

Interesting! did you also check if the hydrodynamics gives good pattern?


Phil Shepperd, modified 5 Months ago.

RE: part module - chess board pattern tracer concentration

Padawan Posts: 45 Join Date: 12/4/18 Recent Posts
I know this question is very old, but the answer is that the PART timestep is smaller than the timestep in the decoupled HDs.  It needs to be the same!!  Odd, I know.