intro story Coast / Estuary

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



Message Boards

Z-layers model, problem with boundary conditions in Delwaq

Marcin Kawka, modified 7 Years ago.

Z-layers model, problem with boundary conditions in Delwaq

I'm trying to model inorganic suspended matter in Delwaq. In sigma-layers model boundary condition works well, however due to lake stratification I would like to use z-model. Delft3d z-layer model of my lake works well with passive tracer so I assume that there is no problem with hydrodynamic part.
In coupling file I have manualy modified the following line:
geometry curvilinear-grid z-layers

In simulation results it looks like there is no influence of the boundary condition. Another strange thing is spatial result (attached picture). I am using 30 layers and in z-layer mode layer no.30 should be the top one, while I see a spatial pattern resembling the shape of the bottom one.

Are there any more changes I should do in simulation files in order to use z-layers instead of sigma-layers?

Marcin Kawka
Anonymous Anonymous, modified 7 Years ago.

RE: Z-layers model, problem with boundary conditions in Delwaq (Answer)

Jedi Master Posts: 333 Join Date: 7/30/20 Recent Posts
Hi Marcin,

This is a known issue. The offline coupling does not work well with z-layers for the moment. You will have to use the built-in coupling instead. See this thread for more info.

Also, Delwaq uses another numbering convention than FLOW (from top to bottom, so layer 1 is the surface layer).

Good luck,