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DELWAQ

DELWAQ is the engine of the D-Water Quality and D-Ecology programmes of the Delft3D suite. It is based on a rich library from which relevant substances and processes can be selected to quickly put water and sediment quality models together.

The processes library covers many aspects of water quality and ecology, from basic tracers, dissolved oxygen, nutrients, organic matter, inorganic suspended matter, heavy metals, bacteria and organic micro-pollutants, to complex algae and macrophyte dynamics. High performance solvers enable the simulation of long periods, often required to capture the full cycles of the processes being modelled.

The finite volume approach underlying DELWAQ allows it to be coupled to both the structured grid hydrodynamics of the current Delft3D-FLOW engine and the upcoming D-Flow Flexible Mesh engine (1D-2D-3D) of the Delft3D Flexible Mesh Suite (or even other models such as TELEMAC).

'DELWAQ in open source' is our invitation to all leading experts to collaborate in further development and research in the field of water quality, ecology and morphology using Delft3D. Feel free to post your DELWAQ related questions or comments in this dedicated forum space. If you are new to DELWAQ, the tutorial (in the user manual) is a good place to start. A list of DELWAQ related publications is available here.

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D-Flow Flexible Mesh
DELWAQ

Cohesive sediments & muddy systems

 


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GMRES Error

ZC
Zachary Cobell, modified 4 Years ago.

GMRES Error

Youngling Posts: 10 Join Date: 5/3/12 Recent Posts
Hi all:

I'm currently getting acquainted with debugging DELWAQ runs and I'm trying to understand where I should be looking for the error I'm seeing below:

Parallel processing with 1 processor(s)

SIMULATION STARTED

INTEGRATION ROUTINE = 16
TIME = 5D 0H 0M 0S . 0.00% Completed
ERROR in GMRES 1
Stopped with error code : 1
STOP 1


Any and all help is appreciated.

Thanks,

Zach
AM
Arjen Markus, modified 4 Years ago.

RE: GMRES Error

Jedi Knight Posts: 195 Join Date: 1/26/11 Recent Posts
One possible cause is that the timestep is too large. Integration option 16 uses fairly tight criteria for convergence by default and if the timestep is too large, convergence may not be reached within the given number of iterations. Unfortunately, it may be caused by segments with a very small volume (relative to the flow rate and the timestep).

The first thing to do is rerun with a smaller timestep.
ZC
Zachary Cobell, modified 4 Years ago.

RE: GMRES Error

Youngling Posts: 10 Join Date: 5/3/12 Recent Posts
Thanks Arjen. Can WAQ use a smaller time step than the output interval from Flow? If so, my problem seems easily solved.

Thanks
AM
Arjen Markus, modified 4 Years ago.

RE: GMRES Error (Answer)

Jedi Knight Posts: 195 Join Date: 1/26/11 Recent Posts
Yes, WAQ can take smaller timesteps:If the hydrodynamic timestep is 1 h, WAQ can take timesteps of 1 h, 30 min, 10 min, etc. as long as the hydrodynamic timestep is a multiple of the WAQ timestep.(Which also means that the hydrodynamic timestep is the _maximum_)
GERMAN RIVILLAS, modified 1 Year ago.

RE: GMRES Error

Youngling Posts: 2 Join Date: 1/25/12 Recent Posts
Hi Arjen:

I'm debugging DELWAQ runs and appear the same error of Zachary. I'm trying to reduce the output time step from 1h to 30 min but the error persist. Do you have any idea to solve this compilation process?

Parallel processing with 1 processor(s)

SIMULATION STARTED

INTEGRATION ROUTINE = 16
TIME = 0D 0H 0M 0S . 0.00% Completed
ERROR in GMRES 1
Stopped with error code : 1
STOP 1


I saw this warning report in the input verification

Messages presented including .lsp file:
Number of WARNINGS : 1


Thanks for your help

Best regards
GERMAN RIVILLAS, modified 1 Year ago.

RE: GMRES Error

Youngling Posts: 2 Join Date: 1/25/12 Recent Posts
I solved the problem!!

Cheers
AM
Arjen Markus, modified 1 Year ago.

RE: GMRES Error

Jedi Knight Posts: 195 Join Date: 1/26/11 Recent Posts
Good to hear that - how did you do it?
YX
yu jia xin, modified 2 Months ago.

RE: GMRES Error

Youngling Posts: 5 Join Date: 12/1/18 Recent Posts

Hello, I want to ask you how you solve this error, error in GMRES, I suspect that there is a problem with the hyd file, but there is no error in my hydrodynamic calculation, and it is 0 warning 0 error when running waq1, so I would like to ask how this should be solved, thank you!

AM
Arjen Markus, modified 2 Months ago.

RE: GMRES Error

Jedi Knight Posts: 195 Join Date: 1/26/11 Recent Posts

There is no relationship between the numerical methods used in Delft3D-FLOW/D-FLOW-FM and the methods in DELWAQ (well, with the exception of integration methods 19 and 20, but they are only applicable on regular grids). Therefore you cannot conclude anything about the fact there were no errors in the hydrodynamic calculation.

Also DELWAQ1 merely processes the input file - it does not check that the hydrodynamic database is free of problems.

That said, there must be something in the hydrodynamic database that is causing this. You may want to experiment with the constant DRY_THRESH (which controls the minimum thickness of water for a grid cell/segment to be regarded as wet) or the constants that control the iteration in GMRES - MAXITER and TOLERANCE