Migration status

  • Home Page: Activity map.

intro story DELWAQ

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.

** PLEASE TAG YOUR POST! **

 

 

Sub groups
D-Flow Flexible Mesh
DELWAQ

Cohesive sediments & muddy systems

 


Message Boards

Where is settling velocity included in vertical direction of transport eq.

GS
Gholamreza Shiravani, modified 1 Year ago.

Where is settling velocity included in vertical direction of transport eq.

Padawan Posts: 65 Join Date: 6/25/16 Recent Posts

Hi D3D-Delwaq community,

could you tell me, in which subroutine is the concentration (CONC) computed? In processes (waq_process) the CONC is a substance and other processes will be calculated through concentration. But which subroutin does compute the CONC? it comes from AD-transport equation. But which subroutine in waq_kernel is the transport equation for amass or CONC? 

GS
Gholamreza Shiravani, modified 1 Year ago.

RE: Where is settling velocity included in vertical direction of transport

Padawan Posts: 65 Join Date: 6/25/16 Recent Posts

Dear Delwaq users, I found the answer :). It is considered in  trase2.f (line 200-Downward advection) in waq_process.

AM
Arjen Markus, modified 1 Year ago.

RE: Where is settling velocity included in vertical direction of transport

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

The strategy in DELWAQ is to compute the mass balance - everything is converted to mass fluxes, these are summed and then the concentration is calculated from the mass and the volume. This necessarily differs per integration option. I fyou want to know the details, have a look in the routines dlwqn* - these are the main routines for each integration option.

GS
Gholamreza Shiravani, modified 1 Year ago.

RE: Where is settling velocity included in vertical direction of transport

Padawan Posts: 65 Join Date: 6/25/16 Recent Posts

Thanks Arjen. In sedim.f, the sedimentation flux (line 179,180 and 338) is calculated from CONC results. But how sedimentation flux will change the CONC?

AM
Arjen Markus, modified 1 Year ago.

RE: Where is settling velocity included in vertical direction of transport

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

That is done i the very same way as all other fluxes: DELWAQ keeps track of the influence a particular flux has on a substance via a table of "stoichiometric" coefficients. For suspended sediment two fluxes are important: a flux from the water phase to the bottom material and the vertical transport (sinking of the material). Both are stored in the PMSA array, but have a different character - determined by the process definition. The exchange of material from the water phase to the bottom is a regular flux and represented by two stoichiometric relations:

dMwater/dt = - sedimentation flux

dMbottom/dt = + sedimentation flux

(Note: M is the mass in the segment)

For the sinking the flux as calculated is interpreted as a "flow velocity" on top of the flow prescribed by the hydrodynamics.