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

ERROR in GMRES 1 - waq simulations

José Rafael Cavalcanti, modified 1 Year ago.

ERROR in GMRES 1 - waq simulations

Youngling Posts: 6 Join Date: 10/21/18 Recent Posts
I am having problems with my waq simulations. The solver does not reach convergence and I can't understand why. Checking my monitoring file it does not show any NaN in the monitoring points nor any wrong mass balance due to boundary conditions. I am reducing the time step, reaching 30s already but nothing is changing. Is there anything else I can look for in order to solve this problem?
I am simulating a reservoir for a rather short time span (2.5 years). The reservoir has a water level drop of around 8 meters and it returns to the maximum water level by the end of the simulation. The error occur at the end of the first year, where there is no relevant wet- and dry-ing of computational cells taking place. At this point in the simulation, the water levels are already down to the maximum depth but it only rises after 1.5 years and keep rising untill the simulation end. To be more efficient a brief summary of the simulation is:
- Z-layer grid;
- Hydrodynamics for waq generated using the built-in option in FLOW considering a 6hrs time step. I was using 1 day time step to write the results but the problem remained;
- Integration method: 15;
- Time step in waq 30s;
- Zthreshould 0.01 m;
- Emersion option set to 1 in .inp, but if set to 0 does not change the outcome;
Does anyone has a clue where I can start searching for problems?
Gholamreza Shiravani, modified 1 Year ago.

RE: ERROR in GMRES 1 - waq simulations

Padawan Posts: 65 Join Date: 6/25/16 Recent Posts
Hi Josa,
the answer is changing the Parameters related to Dispersion in Input file. Try to reduce them and run again. I hope it works.