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

About running delft3d flow

chen ling, modified 6 Years ago.

About running delft3d flow

Youngling Posts: 14 Join Date: 1/2/12 Recent Posts
Dear everyone,

I am doing some simulation of estuary flow, and with the number of grids are 898*538=483124, when I run the model, it doesn't work normally with the error as"in double array allocation of wrkb2 Contact Deltares", this error means the number of grids is too large? could some one tell the reason and how to resolve this problem?
Thanks in advance.

Best wishes,

Chen ling
Qinghua Ye, modified 6 Years ago.

RE: About running delft3d flow (Answer)

Jedi Council Member Posts: 612 Join Date: 3/2/11 Recent Posts
Dear Chen ling,

Yes, indeed it is because of the size of array exceed the limitation of 32-bit executables. You can try the following:

1) using a 64-bit exectuables. At present stage we provide 64-bit executables on Linux platform with our standard support through service package. Or you can compile yourself using the open source code on linux platform. For the 64-bit executables on Win64 platform, I believe it is also included in the open source code, even though it is not official supported. In brief, try linux 64-bit executables, otherwise try to compile a win64 version and try to run the model.

2) using domain decomposition to split the model into smaller subgrid. Refer to Delft3D-FLOW manual section B.14.

3) using nesting to focus on the smaller area. Refer to Delft3D-FLOW manual section F.