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

Error when starting simulation in FLOW

Esther Espinoza, modified 2 Years ago.

Error when starting simulation in FLOW

Padawan Posts: 25 Join Date: 4/6/17 Recent Posts

Hi, I really hope someone can help me. I want to start a simulation in Flow and as you can see in the attached figures, I think I'm following the correct steps , but I can't even choose the .mdf file.

After I created all the files and the .mdf I select the working directory (folder with all files including .mdf) choosing the option of the Flow menu, but When I click on "Start" to run the simulation a small window to choose the .mdf file appears with "default.inp" so I click on "browse" to search the file in a different folder (because even if I previously defined the working directory, that folder doesn't open so I need to change the folder) when I find the .mdf I select it but a message appears saying "Switching to other directory not allowed here. Please, stay in current directory and try again".


I don't know what I'm doing wrong. When I click browse the directory is C:/ but my working directory folder is on a external hard drive F:/. I know that is not the problem because I moved my folder to C:/ but the error continued.


Thank you for your help.