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

Opti Model

Ed Atkin, modified 7 Years ago.

Opti Model

Padawan Posts: 27 Join Date: 3/27/12 Recent Posts
Can anybody please tell me whereto fnd the scripts for wave schematization method - Opti model.

Ben Williams, modified 7 Years ago.

RE: Opti Model (Answer)

Jedi Knight Posts: 114 Join Date: 3/23/11 Recent Posts
Hi Ed,

OPTI is proprietary software for Deltares. As far as I am aware, it is not released to the general public - and if it was, it would be reasonable that you would have to pay for it.

However wave reduction is not too complicated and there are a few ways of doing so.

Simplest is the Energy flux method. There are a few ways to do this if you search the literature. Its simple to do and you could even do it in excel if you wanted.
Second is to use adapt the Energy Flux method, but modify it by contribution of each wave condition to total transport using a simple CERC-type equation as a target for LST - although I would not recommend this.
Third is to use a profile model to look at contribution of each wave condition to the total transport (cross-shore and long-shore).
Fourth is to use a global optimization method to 'evolve' the probabilities of each contribution so that you end up with just a handful of wave conditions that are representative of the wave climate, within a given error.

Methods 1:3 are very easy and you can play around with them in all sorts of ways to get various answers.

Method 4 is a bit more complex but eminently programmable in Matlab or Python, for the simple case of waves only. It takes a while to derive your answer and the quality is not always significantly better than using the simpler methods. However with Method 4 you can start to get much more complex with your target patterns around inlets etc. This is significantly more challenging (and therefore more fun).

Good luck.