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! 

 

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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: 
/web/delft3dfm/forum

Post your questions, issues, suggestions, difficulties related to our Delft3D Flexible Mesh Suite on the new forum.

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** PLEASE TAG YOUR POST! **

 

 

Sub groups
D-Flow Flexible Mesh
DELWAQ
Cohesive sediments & muddy systems

 


Message Boards

Engelund and Hansen formula causing error in sediment inflow

GB
Gyan Basyal, modified 6 Years ago.

Engelund and Hansen formula causing error in sediment inflow

Youngling Posts: 7 Join Date: 5/16/12 Recent Posts
Hello everyone,

I have set constant discharge and "sand" inflow of 2000 m3/s and 0.15 kg/m3 respectively at the inflow boundary. Using default transport formula (Van Rijn 1993), there is no problem. However, using Engelund and Hansen formula, I have fluctuating sediment inflow at the boundary. Additionally, there are suspended and bed load components, which shouldn't be the case with this transport formula. The suspended load component is equal to the user-defined sediment input (0.15 kg/m3). It's the bed load component that is fluctuating. Its magnitude is comparable to the suspended load.

I have run it in Delft3D versions 3185 (tag), 3426 (tag) and 3504 (trunk). All have this issue. I see that the bed load component is zero until the spin-up period is reached.

My transport formula file has following content:

1 IFORM
#1
1
#

I would appreciate any help. Thanks in advance.

-Gyan
Qinghua Ye, modified 6 Years ago.

RE: Engelund and Hansen formula causing error in sediment inflow (Answer)

Jedi Council Member Posts: 612 Join Date: 3/2/11 Recent Posts
Hi Gyan,

You might specify the SedTyp in .sed file to be "bedload", instead of "sand". Engelund and Hansen formula is in general a total load transport formula, is it?

Regards,

Qinghua
GB
Gyan Basyal, modified 6 Years ago.

RE: Engelund and Hansen formula causing error in sediment inflow

Youngling Posts: 7 Join Date: 5/16/12 Recent Posts
Hi Qinghua,

Thank you very much. It worked. Yes you are right that Engelund and Hansen is a total load formula. It is strange that GUI only has the options "sand" and "mud." It would have taken me long to figure it out myself.

Using Engelund and Hansen transport formula I was able to run the model with 1 core both in windows and Linux environment (using MPI). But it stops executing when the number of cores is two or more. I should probably start a new thread for this problem.

Thanks,
Gyan