At this page you can post questions or start discussions on general topics related to Delft3D Flexible Mesh.

Please select a proper category below (if possible), to post your message or reply to an existing post. Please add tags to your posts to simplify searching.







Message Boards

mdu and ext files context

Mohammadreza Khanarmuei, modified 2 Years ago.

mdu and ext files context

Youngling Posts: 2 Join Date: 10/24/17 Recent Posts

Hi There,


I am trying to do data assimilation into D-FLOW by OpenDA and now I'm rebuilding OpenDA's developer examples to become familiar with its methods and materials. The example, which I attached it to this inquiry, is a simple estuary with discharge for the east boundary and astronomical water level for the west boundary. Since ensemble Kalman filter as a data assimilation method needs to add some uncertainty to a boundary, the time series of noise has been introduced at the west boundary with the value of zeroes, but it will be filled with the noise values once OpenDA starts to run.

The problem that I've encountered is that ".mdu" and ".ext" files which OpenDA developers have created are different from my files. I noticed that their version of D-FLOW was different from mine. I would be thankful if you could please let me know whether the version of D-FLOW is the reason for this difference or not? Moreover, What should I do to address this problem? Because I need to provide .mdu and .ext files similar to their example files to let OpenDA interact with D-FLOW. 
Information about this example can be found in the user manual of D-FLOW Flexible Mesh, Chapter 19, page 294.

In addition, I've tried several times to save ".tim" format of noise time series at the west boundary, but I couldn't. I should mention that I am using Delft3D FM Suite 2017 HMWQ  

Attached please find developer's example materials and my materials.

Thanks in advance for your time and consideration.


Best regards,


Michal Kleczek, modified 2 Years ago.

RE: mdu and ext files context

Padawan Posts: 55 Join Date: 10/23/14 Recent Posts

Dear Reza,

The format that you are using, is what we call the 'new' external forcing file format. The format itself is not that new and it was introduced a few years ago (I think already in the first release). Please note that there are still models that are using the old format (e.g. the one you got from developers). We are trying to extend functionalities of the new format and slowly phase out the old format. We try to be as much backward compatible as possible, hence the confusion. 

For you it should not matter and you should be able to use the new format. In this 'new' format instead of extra *.tim files,  information is stored in the *.bc format with a more block structure. That is why you don't need '.tim' exporter for boundaries anymore. Instead you should export Boundary Condition file (.bc) and within it you will find all necessary information (time series). In case you have some inconsistencies or problems with OpenDA and the newer external file format, please let us know so we can inform OpenDA developers that they have some improvements to do.

For further reading about bc format I recommend to take a look at our D-Flow_FM_User_Manual and following locations:

  • section Physical information
  • Appendix B, section B.5.2 New style external forcing (boundary conditions only)

Please let us know if you have any further remarks. 

Kind regards,

Michal Kleczek,