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

Waves forces and spurious alongshore current

Antonio Ruiz, modified 3 Years ago.

Waves forces and spurious alongshore current

Youngling Posts: 1 Join Date: 12/4/14 Recent Posts

I would appreciate some help related to this issue:

- I ran a coupled model (Flow+Wave) based on a simple bathymetry (plane and symmetrical beach, east-west orientation). All forces I used are orthogonal to this beach, so only velocities in v-direction (south-north in my model) were expected.

- To reduce boundary effects I set a nested grid (coarser grid only for waves; a finer grid for flow and waves actions).

After running this model, a horizontal (u-direction) current appears close and parallel to shore, because of waves forces for Hsig>2 m (Jonswap spectrum). These forces are originated in coarser grid boundaries and I cannot eliminate them by increasing roughness or enlarging coarser domain.

Any idea why this happens?

Thanks in advance. Best regards,