psinton@aquageo.us

discrete features cannot be switched on and off during a run. you woud have to stop the run, add discrete features and start the run again.

Pete

Are you plotting the zero-pressure isoline or something else. What mode are you using (confined, phreatic, unsaturated)? If you plot head isolines you should see the effect of the pumping well. If you don't, maybe there is something wrong with your model, or perhaps the rate is too small to see any affect.

To plot drawdown, open the DAC, create a user data distribution (data panel) of nodes. Set this new distribution as the current variable to edit and select all the nodes. Use the expression editor to compute the head at time zero minus the head at some time during the pumping, and then assign that expression to the nodes. This assumes you have saved time steps you want to compute drawdown.

There are a lot of very efficient ways to compute and view drawdown. Elevation of "groundwater" is total hydraulic head.

Pete

You have to activate BC nodes as the tunnel advances, which can be set up using a "modulation function". To do add such a function, in the data panel, right-click (for example) "hydraulic-head bc", select "add parameter" and then select "modulation function". This will add an editable variable beneath hydraulic had bc that you can set up just like any other nodal variables.

Another approach would be to used transient material properties, simulating the advancing tunnel by increasing the K. You would still have a BC at the tunnel entrance to simulate discharge from it.

Pete

"Time series" are only used for "boundary conditions", not for material properties. Material properties are made transient by right clicking, for example, Kxx and selecting "Make transient..."

Pete

Probably a problem with the shape file you are using to specify super-elements

Pete

The procedure Carlos is referring to is to set up a selection of nodes you want to export head data for, then in the data panel right click "hydraulic head" and export data for the current selection (if transient, options will also be available). Such exports can also be done from the view settings panel.

Pete

Unfortunately, Carlos is correct. Version 6, and earlier versions of FEFLOW, allow a "parameter expression" on elemental properties only, two of which are actually boundary conditions (in/outflow on top/bottom and source/sink). Recharge could be used to simulate ET if your model can be set up to simulate ET (negative recharge) only in layer one. Otherwise, you would have to use the source/sink "material" but this is further complicated by its odd units: your parameter expression would have to account for the control volume associated with this "material" (which could be specified and accessed via an elemental user data distribution).

I once tried doing something similar using a parameter expression on source/sink and it did not work so well, which leads me to think that simulating ET this way might not work so well except in simple cases.

There are no "parameter expressions" available for "Boundary Conditions (BC)"

Another solution, which would probably work well, would be to program an IFM module to handle ET using flux or well nodes (well nodes would be easiest). Let me know if you want help with such an approach.

I think the ET video would still be applicable, but the URL is broken and has not been fixed.

Pete

from the help: "In case of interpolating between time series (time-varying link type) FEFLOW can interpolate values at the time stages of the time series, or it can also interpolate between the time stages, e.g., to consider the translation of a flood wave between two locations along a river."

So, if you set up a link to a database file that contains time series data for each xy location, then feflow will set up power functions (time series) for each boundary condition it sets at a node.  Often a model will have fewer points in a time series than time steps, so feflow can also be set up to also linearly interpolate the boundary condition value at a time step that falls between to points in the boundary condition's time series.

Pete

An IFM might be the best solution

ok, I think I get it.  You're probably using cauchy nodes to simulate net evaporation from the lake surface.  But, you should be able to compute that rate knowing the evap rate and area of the lake and that should be equal to the cauchy discharge.  A more realistic and numerically stable approach would be to either add the net evap rate to the abstraction rate for the well or simulate net evap using negative recharge at the lake surface in conjunction with the abstraction well.

Pete