Denim Umeshkumar Anajwala

Hi Leelja,

I would suggest to put the 35000 mg/L as initial only at the seaside part of the domain and have 0 mg/L in the rest of the domain, likely where you know there's only freshwater.
Also, all inflowing BC's on the freshwater side should have a 0 mg/L mass BC.

Apart from the mass transport, I would also suggest to run the model as flow only using the van Genuchten, just to make sure this is stable. If the head solution is already unstable, you have to fix that first before working on the transport.

When the model is being slow with constraints, I would assume they are frequently being triggered during the run. You can easily check that by saving a .dac file and plot all mass BC's. Then you can cycle through each time-step and check. A frequent - and maybe not desired - triggering of constraints can often be due to instability of the model, i.e. over- or undershooting of the primary solution (i.e. mass concentration). If this is the case, you should try stabilizing the model by adjusting the mesh first, then work on other parameters like dispersivities or solver settings. A general good idea with such a combinded unsaturated and mass transport approach is working with the FE/BE time-stepping scheme. Further, try putting a growth factor (starting at small values 1.05 to 2, you have to do test runs for optimal behaviour).

Since it is being unstable when using van Genuchten, I would also suggest to have a look at the saturation and its distribution in each time-step. You might also have to work on the mesh in order to better represent the saturation, or choose different van Genuchten parameters for adjusting the saturation solution.

Clicking on 'Disconnect' should only disconnect the selected connections, at least with the latest version of the license manager NetLM. However, there's usually no risk in disconnecting all users, as the FEFLOW client will immediately try to reconnect, and will re-allocate the license without the user seeing that the license was lost.

Unfortunately there's currently no such option - so the only way is by using the ASCII dac file.

Thanks a lot for your answer.

Hi.

I was using Feflow and my computer just crashed. After a restart I see the floating license server is still occupied by my previous connection. When I try to kill this connection the only option is to disconnect all the 7 users? Look at the image. Anyone knows how to kill just one connection and avoid disconnecting other users? Don't want to mess their work.

Thanks in advance, bye.

[url=http://postimage.org/][img width=200 height=153]http://s7.postimg.org/rsbtyjjyj/Capture_feflow.png[/img][/url]
[url=http://postimage.org/index.php?lang=spanish]imagen[/url]

Hi Blair,

one little correction: Excluding free&moveable still leaves the options for phreatic and unsaturated - besides confined.

Best regards,
Peter

There's no specific IFM approach. In our work, we've mostly been using MFC and - used also for FEFLOW itself - Qt.

Hi there,

I put both feature requests (definition of DOI/MD and export of time series from flow panels) on the wishlist of 6.2, so our developers can decide whether they will implement them. Currently, there is no export for the internal budgets possible.

Mathematically, there is a difference between transfer B.C.'s for 2D and 3D models:

In a 3D model, the exchange area of a river is defined either on slice faces (in most cases orientated more or less horizontally), or join faces (vertical) between two slices.
In 2D, the transfer area can only be regarded as a 1D line, due to reducing the system by one dimension. (For theoretical background: The vertically avaraged equations for 2D problems according to Dupuit are being introduced in chapter 1 and 2 of the FEFLOW reference manual.)

From a practical point of view, there is no z-dimension and consequently there are no velocity components in z-direction either.
Any transfer boundaries in 2D models on slice faces can only consist of element edges. Note that any refinement of such elements yields new element edges, possibly resulting in unwanted additional exchange rates! See also the attached picture.

There is a difference between edges at outer boundary of a model and edges located inside the model: For outer edges, there is only one adjacent element, while for inner edges there are two adjacent elements. In the latter case, the length of the edge (2D) or area of the face (3D) is taken twice. At all outer boundaries, the length or face is only taken once.


Looking at the physical units, the resulting exchange rate is [L³/T], L = length, T = time.

[list]
[li]In [u]2D horizontal confined models[/u], this amount results from the difference in the potential between surface water and groundwater [L] * the edge length [L] * the transfer rate [L/T].
[/li]
[li]In [u]2D horizontal unconfined models[/u] the exchange rate results from the potential difference [L] * edge length [L] * saturated thickness [L] * transfer rate [1/T]. The saturated thickness is being calculated by the difference between calculated groundwater surface elevation [L] and the elemental distribution of the parameter "Bottom elevation" [L].
[/li]
[li]
In [u]2D horizontal unconfined models[/u] or models with the 'free' mode (3D), one can also work with [b]depth integrated conditions[/b]. The boundary flow at fluid-flux boundary conditions is highly interlinked with the hydraulic head (groundwater level) inside the model. In some cases during the iterative solution process or over time in transient models, it may happen that a slightly lower hydraulic head leads to less inflow and vice versa, so that finally no inflow is left and the model becomes dry. For such cases, FEFLOW provides the Fluid-flux BC as Integral BC. In this boundary-condition type, the saturated thickness is not changed during the model run. In 2D models, the input values for the boundary condition are depth-integrated flux values. In the 3D 'free' mode, the model uses the original layer stratigraphy for the calculation of the boundary-condition area, no matter what the current water level is.
When a so called integral transfer BC is applied, the exchange rate is obtained from the potential difference [L] * edge length [L] * integral of transfer rate [1/T] over depth [L].
[/li]
[li]
In [u]3D models[/u], depth integrated transfer boundary conditions become only effective when using the 'free'
mode. In all 3D modes, the transfer rate is calculated from potential difference [L] * face area [L²] * transfer rate [1/T].
[/li]
[/list]
Note: In 2D horizontal cases, when using either the confined approach or the unconfined approach with integral transfer boundary conditions, the transfer rate parameters as specified must incorporate the desired depth.

For many practical cases, it is needed to calculate a transfer rate (or leakage amount) between groundwater and surface water by an exchange area orientated horizontally (lakes, shallow ditches, ponds...) or even a combination of both (canals, drains). Since the 2D approach does not take any z-components into account, it is highly advisable to work with a 3D model in this case. In a vertically, essentially homogenous exchange situation (e.g. a narrow, yet deep creek) where the z-components can be neglected, a 2D approach might be sufficient.

Hi~

I'm running MU2012.
Is there a multilink input function? (i.e Pipes of this kind : 2@1x1, 3@1x1...etc.)
I couln't find any dialogues related to this function.

Thank you for your help.