Denim Umeshkumar Anajwala

Another option would be using a stored selection as the plotting target: You can select all elements (in a layer or in 3D) where h<elevation (this is the case above the water table) via 'Select by Expression', then store the selection and plot the isolines onto this selection by clicking it in the'Selections' panel before double-clicking to show hydraulic head.

In FEFLOW, the simulation is done in 3D (so it's not a collection of 2D models for the aquifers and aquitards). Thus the influence of the water level in one aquifer onto another aquifer depends on the properties of the layer in between. If you don't see any influence, the aquitard in between probably has a very low hydraulic conductivity.

1. You can set up an elemental or nodal expression, dividing the resulting Darcy velocity by the porosity.
2. FEFLOW does not use any dry cells. In the dry layers in phreatic mode, the hydraulic conductivity is reduced linearly with saturation of the element, but the element stays part of the simulation. Thus recharge is still also added on top of the model (into slice 1). This will lead to a vertical gradient in hydraulic head, as recharge has to be routed from the model top to the water level. The phreatic approch is a generally very stable solution for regional model with a predominantly horizontal groundwater flow. In more local situations, or situations with vertical flow dominating, I'd recommend to rather use a variably saturated/unsaturated approach applying Richards' equation.

The effective (horizontal) conductivity at a slice in between an aquifer and an aquitard is a volume-averaged mean.

An undefined hydraulic head points towards some quite severe numerical problems in the model. I highly recommend to contact our user support (mike.de@dhigroup.com) and provide them with the model for checking.

For discrete structures, such as faults, you can use FEFLOW's feature 'Discrete Features'. Have a look at the manual and/or help system for details!

Hi Nate,
Could you share the cube with me? I'd like to check it... (psc@dhigroup.com).
Cheers,
Peter

The concept in FEFLOW is still the same: flow and transport are always solved in parallel, so there is no option to load a flow solution and run transport on this basis.

Thanks for the pretty cool example. We might not go as far in terms of classification in the first run - but will keep this in mind for sure.

There are both an outer and an inner iteration. The outer one is executed in all cases where you have a non-linear equation system to solve (unconfined aquifers, unsaturated simulation, density-dependent simulation, ...). The inner one is the solver iteration, and this one you do not have in case of a direct equation-system solver. The non-convergence message refers to the outer iteration that is controlled by the error criterion on the Numerical Parameters page of the Problem Settings dialog.