Posted Tue, 04 Sep 2007 10:53:44 GMT by chrisoula

I am trying to simulate a 3D seawater intrusion model. I defined boundary condition of constant mass in the coastline border and I transformed the hydraulc head of seawater to equivalent fresh water hydraulic head. I also used free and movable opion for the first slice.
After simulation for 10 years, high concentrations of Cl occur in a distance of some km from the coastline. My problem is that concentrations are not increase with the depth. No saltwater wedge is oserved.
Does anyone has any suggestion???
I would also like to ask, how could I visualize the wedge???
Posted Thu, 06 Sep 2007 09:56:08 GMT by Hydrobert
Hello chrisoula,

a saltwater wedge will de observed when the model runs density-dependent.

1. Therefore you have to check the set of the global density ratio in FEFLOW. The density ratio is defined as the ratio between the density of the fresh water (min. concentration) and that of the saltwater. As you set the equivalent fresh water hydraulic head, you used the density ratio (depth dependent) already.
2. To run the model full density-dependent you have to check the specific option setting to incorporate viscosity and the extended Boussinesq approximation.
3. For the coastline border it is necessary to set a constraint of the mass boundary. For a minimal flux is set to yes and 0 mg/l m3/d. This is necessary for the validation of the set of the constant mass boundary condition at the coastline border. After setting this constraint, the mass boundary condition is only valid if water run into the model.

To visualize the wedge, you have to check the control output settings in the simulator. Datas could be saved automatically during the simulator runs. Afterwards you can load this data file with the FEFLOW explorer to extract pictures or movies.
Posted Fri, 07 Sep 2007 09:47:55 GMT by chrisoula
Robert, thanks for your help.
I had not incorporated viscosity and the extended Boussinesq approximation.
I will simulate my model again and I wish to visualize the wedge.
Thanks again

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