# 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!

## Message Boards

### Problem in starting simulation

AG

#### Problem in starting simulation

Youngling Posts: 4 Join Date: 11/2/17
hello,
i'm new in this forum.
I'm simulating an easy case of channel (12x100m) with tidal effects. The mesh is 3x3m. When I start the flow simulation, the computation doesn't work, but not errors occurs.
I think happened for wrong boundary conditions introduction.
The domain is square (300x300m)
The model is sea (in the bottom, depth 1m) for 1/3 of the domain, a channel (1m depht) in the middle even for 1/3 of the domain and land for the rest (0m).

What're boundary conditions I have to introduce, only time series water level or other conditions like close boundaries?

thank you

#### RE: Problem in starting simulation (Answer)

Yoda Posts: 1224 Join Date: 1/3/11
Hi Alessandro,

I don't expect a not working computation without errors.

Are you able to run example "01_standard", see the source code page? If not, something is wrong with your Delft3D installation.

Is there a tri-diag-file in your working directory? This (ASCII) diagnosis file might contain error messages.

Boundaries are closed by default: you don't have to model them. Just one time series water level boundary should be enough to model a simple "harbour".

The manual (Delft3D-FLOW_User_Manual.pdf) contains a tutorial for setting up a model.

Regards,