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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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Delwaq2: Scientific reference about numerical methods in Delwaq

GS
Gholamreza Shiravani, modified 14 Days ago.

Delwaq2: Scientific reference about numerical methods in Delwaq

Youngling Posts: 16 Join Date: 6/25/16 Recent Posts

Hi,

due to high diffrences between explicit and implicit numerical methods in Delwaq computations, could you mention a scientific Report/manual about their theoritical applications in Delwaq. I read and know the concise introduction in Delwaq-manual. In Manual it is referenced to :" D-WAQ TRM, 2013. D-Water Quality Technical Reference Manual. Deltares, 4.00 ed", but it is not published and when I search in Internet I found only :

https://oss.deltares.nl/documents/183920/185723/D-Water_Quality_Processes_Technical_Reference_Manual.pdf/9356affd-4453-4fef-9289-48d0a8d043ab?version=1.0

, which has nothing about implemented numeical methods.

 

AM
Arjen Markus, modified 14 Days ago.

RE: Delwaq2: Scientific reference about numerical methods in Delwaq

Jedi Knight Posts: 181 Join Date: 1/26/11 Recent Posts

The manual at https://content.oss.deltares.nl/delft3d/manuals/D-Water_Quality_User_Manual.pdf does describe the numerical integration methods in some technical detail and contains quite a few references to the underlying publications. Is this the manual that you already know? If so, in what way are these references not sufficient - no criticism, just trying to understand your question?

GS
Gholamreza Shiravani, modified 14 Days ago.

RE: Delwaq2: Scientific reference about numerical methods in Delwaq

Youngling Posts: 16 Join Date: 6/25/16 Recent Posts

Thanks Arjen for your answer. I read them but unfortunately I did not find information about how do these numerical schemes deal with the tidal areas (like islands). I have different sand islands that their boundaries are in some times wet and some times dry. I included these in D-Flow  mesh, without excluding them as land. My D-Flow works well. In contrast, Delwaq gives NaN values when the cells are dry and NaN-values are Extended in all parts of domain. When I try an implicit method like 16, it gives the GMR.. error and in .mon-file it recommends to reduce time-step, increase the Iteration number , etc .... but doing these will not solve the problem, at least the time step of 1 sec! . When I use explicit method like 11, the model runs without errors but the results becomes NaN after first time-step! When I see the corresponding map-file, I realize that  NaN-values are started from the islands in my open boundary and Extended to the whole part of domain. I have no substance and only continuity as input.

AM
Arjen Markus, modified 14 Days ago.

RE: Delwaq2: Scientific reference about numerical methods in Delwaq

Jedi Knight Posts: 181 Join Date: 1/26/11 Recent Posts

Ah, that makes it a bit clearer. Treatment of the drying and flooding grid cells is not part of the numerical method perse, but rather of how the flows are applied to set up the transport (before actually solving the equations). The drying/flooding is determined via a constant called DRY_THRESH. By default it is set to 1 mm (0.001 m), but in your case it may be beneficial to set to a somewhat higher value.