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

Bubble plume model not working

Dougal Greer, modified 8 Years ago.

Bubble plume model not working

Youngling Posts: 4 Join Date: 10/28/11 Recent Posts
I posted with regard to this on the general forum but perhaps this is a better place for my query. I have spent some time trying to implement a bubble plume model in a lake but to date I have not managed to generate any currents from the plume. I have read and re-read the manual but can't see anything else to try.

I have created a very simple test case (attached to this post) which should be implementing a large bubble plume in a small grid, but the model output only shows currents in the range of 10^-13 m/s. If anyone has any experience with bubble plumes I would really appreciate it if they could have a look at the attached example. Presumably I have overlooked something very simple.

Many thanks,



Adri Mourits, modified 7 Years ago.

RE: Bubble plume model not working (Answer)

Yoda Posts: 1212 Join Date: 1/3/11 Recent Posts
Hi Dougal,

Your bubble plume works fine. See attached picture.

Bubbles are modelled as a sub grid process, causing inter changing of water from low layers to high layers. It's vertically mixed. It's not modelled as a vertical jet. Thus the (direct) influence on the velocities in the neighbouring points is very small. Especially since your model has a uniform density (uniform salinity and temperature). But if your model has non-uniform densities (non-uniform salinity and/or temperature), the effect of the bubbles will be bigger.