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

Boundary conditions flow and salinity

Esther Espinoza, modified 2 Years ago.

Boundary conditions flow and salinity

Padawan Posts: 25 Join Date: 4/6/17 Recent Posts
Hi ! I hope you can help me with something:

I am modeling flow and salinity of a estuary and I have some questions about the data that is needed to start:

Sorry if this is to obvious to ask, but I am starting to use the model

1) For boundary conditions: Is it necessary that both boundary conditions, flow conditions and transport conditions for salinity start and finish at the same time and are located in the same points? Also, If the data for flow is hourly the data for salinity should be hourly too or can it be daily ? I mean for example:

Flow: Time Begin End Salinity Time Begin End

28 04 2016 02 00 00 -1.45 -1.45 20 03 2014 10 00 00 33 33

It would be ok the example above? The thing is that the data available are not in the same monitoring stations, so tide and salinity data are from different locations and probably won't match in dates and times.

2) For the bathymetry data, Does it matter if the spacial resolution is 5 m at one specific zone of the grid and 50 m in the outer part, and then 100 m somewhere else? Which is the necessary resolution for this type of area? Is an estuary with internal channels of approximately 2 km of width and increasing its width until ending like a gulf with several km of width in the mouth.

The problem is that the data available doesn't have the same resolution for all the study area, because they just collect data at the navigation channel and in the outter part the resolution is too coarse, maybe like 200 m or more.

3) Do you have any recommendations or advices to start modeling salinity and flow?

Thank you so much for your help!