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

About tracers

chen ling, modified 6 Years ago.

About tracers

Youngling Posts: 14 Join Date: 1/2/12 Recent Posts
Hi all,

I want to use the processes of pollutants and tracers to track the time which is costed by water exchanged in lake, I set the processes without decay, but when I run my model for several hours, I found the tracers concentration was decay. thus I am worried the concentration become zero when the tracers arrives at the exit. Could some tell me what can I do to prevent the concentration decay?
Thanks so much.

Kind regards,

Chen ling
Adri Mourits, modified 6 Years ago.

RE: About tracers (Answer)

Yoda Posts: 1224 Join Date: 1/3/11 Recent Posts
Hi Chen Ling,

When you add a (conservative) tracer with a constant value (say 1.0) everywhere, and also use this value at open boundaries and all discharges, the tracer should stay 1.0 during the calculation. If you use a value of zero at open boundaries and/or discharges, the value will decrease during the computation.


chen ling, modified 5 Years ago.

RE: About tracers

Youngling Posts: 14 Join Date: 1/2/12 Recent Posts
Hi Adri,

Yes, I have done that as you suggested, and the result was exactly that I wanted. Thank you very much!

Kind regards,

Chen Ling