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. 
 

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Sub groups
D-Flow Flexible Mesh
DELWAQ
Cohesive sediments & muddy systems

 

 

Message Boards

Delwaq: critical shear stress for resuspension (TaucRS1DM)

GS
Gholamreza Shiravani, modified 1 Year ago.

Delwaq: critical shear stress for resuspension (TaucRS1DM)

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

Hi

how can I define the critical shear stress for resuspension for each Inorganic Materials (IM) in IMS1/S2? There is only one critical shear stress for resuspension after activating Res_DM. After Sedimentation of IMs in S1, the actual S1 will be a mixed of IM1,IM2 and IM3. For any of IMs, there is a seperate critical shear stress for resuspension but we can only Input one value as TaucRS1DM.

The questions:

1-Which critical shear stress will be used for S1 when it consists of IM1+IM2+IM3?

2-Why we can only Input one value for resuspension, while we can Input for each IM ist sedimentation critical shear stress?It makes sense that we Input for each IM ist critical shear stress for resuspension as well, not only one value for TaucRS1DM. However, if we should  only Input one value, which of IMs (IM1 or IM2 or IM3) should be selected to Input ist critical shear stress for resuspension from S1?

3-If we do not define IMs(IM1,IM2 and IM3) in S1/S2, i.e. we only consider IMs (only IM1,IM2 and IM3) and no IM in layer S1/S2, how their resuspensions after Sedimentation will be considered and calculated by Delwaq?

4- When we use only IMs, why delwaq does not ask for their RHOs (their densities)?Which density will be considered for IMs when we do not define IMS1/S2? Is the density indirectly through Sedimentation velocity considered?

AM
Arjen Markus, modified 1 Year ago.

RE: Delwaq: critical shear stress for resuspension (TaucRS1DM)

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

Ad 1.

There is only one critical shear stress for resuspension as this process acts on the whole of the bottom layer.

Ad 2.

See above.

Ad 3.

The resuspension process as implemented requires at least IM1S1 to be present. Without it, there is simply no information on how much material is avaiable on the bottom. Hence, without it there will not be any resuspension according to the set-up.

Ad 4.

Can you clarify why you think densities are required? I do not fully understand your question.

GS
Gholamreza Shiravani, modified 1 Year ago.

RE: Delwaq: critical shear stress for resuspension (TaucRS1DM)

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

Thanks a lot Arjen for your answers. Regard Ad.4 , I found the answer. I should activate the "composition".  But there is a bug: when I activate the densities as editable: " bulk density IM1 (RHOIM1)" and Change the values in "Define Input (.scn-file), the OpenMP does not work (writing CONSTNTS, nothread, DATA,0.0) and in .mon-File I see error of NaN in RHS. But using one processor, it works! It is a bit strange and now I want to see the src of delwaq to know where I can chnage the IM-bulk densities.Do you have an idea?

-Last question: Could you tell me how can I read and connect the Sediment results (from Delft-FLOW) to the S1/S2? should I Change something in src? I see no Information about using the Sediment results from D-FLOW in Delwaq!

Many thanks again for your answers.

GS
Gholamreza Shiravani, modified 1 Year ago.

RE: Delwaq: critical shear stress for resuspension (TaucRS1DM)

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

About Ad 1.:

using TaucRS1IM1 in .inp-file it is possible to Change the critical shear stress for each fraction. The Default TaucRS1IM1 is 0.2NM-2.