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


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OpenDA EnsKF - Crash Delft3D

Mariangel Garcia, modified 6 Years ago.

OpenDA EnsKF - Crash Delft3D


I'm using OpenDA with Delft3D 2D mode with time series boundary conditions. I have only 2 observation location WL and currents, model without DA is stable with 1 minute time step.

I have 15 time series BCs, to perform the assimilation every 30 minutes.

I'm trying to do 15 days simulation, model is crashing with 10, 20 and 30 ensamble I also try to assimilate only one station and it didn't work, so before going further I want to make sure all the setting are correct, I hope you can help me to find out why the model is becoming unstable.

I used the Estuary problem as a template so for the noise configuration file bbStochModelConfig_win32_ifort the setting is like this:

             <vector id="West1"/>
             <vector id="West2"/>
             <vector id="West3"/>
             <vector id="West4"/>
             <vector id="West5"/>
             <vector id="West6"/>
             <vector id="West7"/>
             <vector id="West8"/>
             <vector id="West9"/>
             <vector id="West10"/>
             <vector id="West11"/>
             <vector id="West12"/>
             <vector id="West13"/>
             <vector id="West14"/>
             <vector id="West15"/>
                <armaModel operation="add">
                    <stdDev value="0.032428488"/>
            <vector id="state"/>
           <vector id="North.waterlevel" sourceVectorId="North.waterlevel"/>
          <vector id="Mouth.waterlevel" sourceVectorId="Mouth.waterlevel"/>


and for thed3dModelFactoryConfig_win32_ifort

        <exchangeItem id="West1" type="bound_hq" />
        <exchangeItem id="West2" type="bound_hq" />
        <exchangeItem id="West3" type="bound_hq" />
        <exchangeItem id="West4" type="bound_hq" />
        <exchangeItem id="West5" type="bound_hq" />
        <exchangeItem id="West6" type="bound_hq" />
        <exchangeItem id="West7" type="bound_hq" />
        <exchangeItem id="West8" type="bound_hq" />
        <exchangeItem id="West9" type="bound_hq" />
        <exchangeItem id="West10" type="bound_hq" />
        <exchangeItem id="West11" type="bound_hq" />
        <exchangeItem id="West12" type="bound_hq" />
        <exchangeItem id="West13" type="bound_hq" />
        <exchangeItem id="West14" type="bound_hq" />
        <exchangeItem id="West15" type="bound_hq" />
        <exchangeItem id="North" type="waterlevel" />
        <exchangeItem id="Mouth" type="waterlevel" />

Here some plot from output

When I checked the output from the GUI seems is adding noise only at the first BC

xi_f_0 (iteration=1):
state, State From Black Box Stoch Model Instance - containing:
noise-on-West1-a.o.= 0.057
xi_f_1 (iteration=2):
state, State From Black Box Stoch Model Instance - containing:
noise-on-West1-a.o.= 0.04
x_f_central (iteration=3):
state, State From Black Box Stoch Model Instance - containing:
noise-on-West1-a.o.= 0
analysis_time (iteration=4):
analysis_time= 5.544E4
pred_f_central (iteration=5):
predictions - containing:
North.waterlevel= -0.457
Mouth.waterlevel= -0.474

I hope this info is enough to find out what is the problem,

I am doing something wrong or I just have to increase the nr of ensamble to solve this issue?

Best Regards.