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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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Sub groups
D-Flow Flexible Mesh
DELWAQ

Cohesive sediments & muddy systems

 


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Boundary conditions

KC
Karla Contreras, modified 5 Years ago.

Boundary conditions

Youngling Posts: 1 Join Date: 3/16/14 Recent Posts
Hello everyone
I am modeling a river estuary area. As boundary condition entry downstream water level in a time series and as upstream boundary condition in a total discharge time series. But as a result I see that the river is empty, it's like I was not taking on water.
Change the sign of the inflow, by the increasing number of nodes, but the result is the same

If I could help I would appreciate it.

regards

Karla

attached model

Attachments:

Richard Measures, modified 5 Years ago.

RE: Boundary conditions

Jedi Knight Posts: 178 Join Date: 3/23/11 Recent Posts
Hi Karla,

Do you have any water at the river boundary in your initial condition. Total discharge boundary conditions only work when the boundary is wet at some point along its length. When simulating rivers I usually create an *.ini initial conditions file with a sloping water level or even just a small puddle of water at the upstream boundary to get the boundary going. You can generate *.ini files to do this quite easily using quickin and a text editor by manually specifying water elevation and then setting zero velocity everywhere (see definition of ini file in Appendix A of the manual).

It would be a useful improvement to the total discharge boundary condition if it was modified (in the source code) to allow starting from a dry initial condition and probably not too hard to implement if you or anyone else feels inspired to make the change :-)

Cheers,
Richard
AM
Arjen Markus, modified 2 Years ago.

RE: Boundary conditions

Jedi Knight Posts: 223 Join Date: 1/26/11 Recent Posts

In general - within the sort of problems we solve with Delft3D - you do not want the initial conditions to influence the result over the long run. The initial condition is mostly a nuisance, especially if you have a tidal flow or some other form of external forcing. (It is different if you want to model a transient phenomenon like a dam break or a tsunami). For a parameter like the water level, the transient part dies out within a few tidal cycles. For salinity and temperature this is likely to take much longer.

That said, the numerical difference between a uniform value and a value that may vary over space is of impact only during the time of transition.

Regards,

Arjen