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

Depth averaged velocities off by a factor of 10.

A D, modified 1 Year ago.

Depth averaged velocities off by a factor of 10.

Youngling Posts: 15 Join Date: 9/25/17 Recent Posts
Hello, this post is an update to one of my previous posts. (

I have played around with some parameters to get a decent model. Everything looks fine except that my depth averaged velocities are exactly off by a factor of 10. I'm getting highs of about 0.1 m/s when I should be getting 1 m/s. I have checked the units of all my parameters and they are all in meters. My results for water level accurately describe the local tidal conditions (+/- 1 m). But my depth averaged velocities are wrong.

Any input on what could be wrong greatly appreciated.

Thank you.