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

tidal turbines simulated as porous plates

ANTONIA CHATZIRODOU, modified 7 Years ago.

tidal turbines simulated as porous plates

Youngling Posts: 20 Join Date: 8/7/12 Recent Posts
Hi all,

I am trying to simulate tidal turbines in Delft3d flow as porous plates. There is a loss coefficient representing quadratic friction that needs to be defined. As far as I understand this coefficient has to be <1 but working with the manuals they seem to define coefficients of values 1000. or 800. How this value closs-u=1000. or 800. is interpreted in the module ?

Any advice really appreciated !

Erik de Goede, modified 7 Years ago.

RE: tidal turbines simulated as porous plates

Youngling Posts: 13 Join Date: 1/7/11 Recent Posts
Dear Antonia,

The friction coefficient must be positive; see Section B.3.3 in the Delft3D-FLOW user manual. There is no restriction that this value should be smaller than one.
How to choose this (positive) friction coefficient depends on your application. This can be seen as a calibration parameter.

With kind regards,

Erik de Goede