Coast / Estuary

Coastal systems are among the most dynamic physical systems on earth and are subject to a large variety of forces. The morphodynamic changes occurring to coastlines worldwide are of great interest and importance. These changes occur as a result of the erosion of sediments, its subsequent transport as bed load or suspended load, and eventual deposition. 
Estuaries are partly enclosed water bodies that have an open connection to the coast. Estuaries generally have one or more branching channels, intertidal mudflats and/or salt marshes. Intertidal areas are of high ecological importance and trap sediments (sands, silts, clays and organic matter).
Within the Delft3D modelling package a large variation of coastal and estuarine physical and chemical processes can be simulated. These include waves, tidal propagation, wind- or wave-induced water level setup, flow induced by salinity or temperature gradients, sand and mud transport, water quality and changing bathymetry (morphology). Delft3D can also be used operationally e.g. storm, surge and algal bloom forecasting. 
On this discussion page you can post questions, research discussions or just share your experience about modelling coastal and/or estuarine systems with Delft3D FM. 




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


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How to reduce the running time?

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How to reduce the running time?
reduce running time running speed
Answer (Unmark)
6/16/17 4:56 PM
I'm asking for help. I met a problem about the running time of delft3d model.
My model resolution is about 1000 km, the grid is 506*388,the time step is 5 min,and my computer has 2 CPU of 12 cores. I run FLOW with WAVE-online for about a mouth, this process spent about 25 hours, is the running speed normal ? And how to as possible as to reduce the running time? Can the output variables be reduce in order to reduce running time by modifying source code? And how?

Any advice / help would be appreciated


RE: How to reduce the running time?
Answer (Unmark)
6/24/17 2:31 PMas a reply to Liu Karl.
Hi Karl,

Depends on the model settings and hardware settings, 25 hours seems to me not a strange number.

There are a few ways to improve the performance, such as parallel, etc.

Model settings definitely are another way, such as, your suggestion of output variables, interval to be coupled with wave etc., even a better grid can be helpful.

The output variables can be defined not to be in the output files. You may selelct those in GUI/output page.

Hope this is helpful,

RE: How to reduce the running time?
Answer (Unmark)
6/27/17 3:47 PMas a reply to Qinghua Ye.
Thanks for your reply !

About the parallel, when I run flow alone on linux, I input 'mpirun -np 22 d_hydro.exe config_d_hydro.xml', the runtime will be reduced.

But if I run flow with wave on linux, I input'mpirun -np 22 d_hydro.exe config_d_hydro.xml & wave.exe r17.mdw 1', the runtime will be not reduced, instead,it is increased.

Do you know why?

Thank you!
RE: How to reduce the running time?
Answer (Unmark)
6/27/17 6:14 PMas a reply to Liu Karl.
Hi Karl,

Yes, to use more cpus/cores doesn't necessarily improve the performance in some cases. For example, when the model is not so complex, parallelization might lead to that the communication time is even longer than the computation time. Then it is not necessary to have so many partitions. r17.mdw is a small model.