• Re: Vertical Exaggeration


    Wow ... that sounds like a bug to me!! The exaggeration should be a purely visual thing, completely independent of the underlying mesh data!!!

  • Re: Depth-dependant Evaporation

    Hey Andrés.

    To my knowledge there currently isn't an easy way to reference z_WT. It's simply not available as a variable in FeFlow. And it's not that easy of a value to find in the first place (since there might be more than one "water-table" at a given x/y location!).

    We developed an IFM module to find the "water-table elevation" and export it to a file for visualisation in a GIS. I would use a similar approach: Write an IFM module to set the evaporation rate based on the water-table elevation, which I'd sear for first. Unfortunately, this doesn't help you much, since I assume you don't wanna go to such an advanced extent as using IFM models/code writing.

    Can you explain how your evaporation rate should be calculated and specified in FeFlow (i.e. fnx(z_wt) and the type of BC you plan to use)?!

    Chris
  • Re: "No boundary conditions" Does it mean impervious boundary?

    [b]Thank you so much Peter

    I understood the problem. That comes from the nodal basis calcuation in FEM.
    Because I have interests in potential (i.e. head) in many cases. I did not check and think the FEM procedure.

    Thank you again [/b] :D :D :D
  • Re: "No boundary conditions" Does it mean impervious boundary?

    [size=10pt][b]Thank you so much, Thierry.

    I think that you mean that no boundary condition is no flow, i.e. impervious boundary and the vector cross the boundary is just fictitious. Is it right ?

    In my question, the VERTICAL means just crossing boundary NOT UP and Down...and I just used 2-D model to test the no boundary condition setting. I am still confused because of the resulting vectors in the boundary which has no boudary conditions.

    The sample FEM file (Dynamic_river.fem) has no boundary conditions in left, up and down sides but the boundaries have initial head conditions. Is there any possibility the initial head condition make the boundary as a 1st kind boudary condition ?

    Also, if I use the FLUX ANALYZER (in POSTPROCESSOR MENU) to check the in or out flux flow, there are values still in the boundary which was not applied any boundary condition.  I do not understand yet this problem.....Please help me if you (anybody also) know further about this. [/b][/size]



  • "No boundary conditions" Does it mean impervious boundary?

    [b][size=10pt]Hi.. Feflower...

    This is simple question. If I do not prescribe any boundary conditions on the boundary, does it mean that the boundary is impervious?

    To check this, I made simple model and ran the model but the boundary (on which no boudary conditions) nodes show the some normal velocity vector. I think it is somewhat strange.

    You can also check this problem by using DYNAMIC_RIVER.FEM which is included in the folder ../feflow5.1/demo/examples/femdata. This FEM file has boundary conditions only in left side as a transfer type (type 3 B.C.). But if you run the model, you can see many vectors on other boundary has the normal component.

    As far as I known, if no coditions meas the impervious boundary, there should be no vertical (or normal) component in that boundary.

    Please let me know this more clear.

    Thanks     8) 8) 8)

    PS : Direct contact by using my e-mail, <hskim@kwater.or.kr>, is surely welcomed and acknowledged. [/size] [/b]
  • Re: Recharge definition (basic question)

    Hi Elad,

    there's not one 'best way', but there are several constraints to consider when defining a concentration for recharge:

    :( You can use a first kind condition only in the case that at the top nodes recharge is the only flow. If you have additional lateral flow, and recharge only contributes a little bit to the total amount of water in the top slice, you'd get too much mass into your model by putting a first kind bc.

    :( Source/sink is not applicable as it defines a source/sink per volume of the element - so your known values of recharge concentration won't fit.

    :) So the only way is to use a 2nd kind boundary condition (unit is something like g/(m²d) all over the top. You can calculate the value you need by recharge multiplied with recharge concentration.

    [size=14pt][color=red]![/color][/size] You need to use 'divergence form' of the transport equation when using 2nd kind mass bcs. Using 'divergence form' might lead to difficulties at outflowing boundaries like pumping wells.
    Best regards,
    Peter

    --
    Dipl.-Ing. Peter Schätzl,FEFLOW Support Services
    WASY Gesellschaft für wasserwirtschaftliche Planung und
  • Recharge definition (basic question)

    Hi,
    i wonder what is the best way to define the Recharge (Rain that infiltrate to aquifer)

    so far i used 'in/out flow on top' with positive value for flow
    now i want to add transport too ...
    so should i use source/sink? 1st kind boundary? else ?

    say i have a recharge with 50 mg/l allover the area what value shoud i apply?
  • mass conservation at pumping wells???

    Hi there,

    I wonder if in mass transport simulations, the concentrations at observation points located at nodes corresponding to pumping wells are representative of water fluxes and concentrations entering the well from all surrounding cells - including for wells connected to more than one layer (i.e. mass conservation)?

    thanks

    thomas
  • Re: horizontal and vertical cross sections / bug in FF 5.3?

    Peter

    I have the same problem as Hector on this.

    On the left side of the 3-D layer configuator is a slice list for slice with buttons for "status" ("fixed", etc.) and "button" ("view...") for each slice. When I click on "view", a new dialog opens. This dialog has a plan view of the slice and two windows, one to the left and one to the bottom, for displaying the slice configuration cross-section for the position of the cross hairs in the plan view. I do not see the cross-section profiles. Each profile window has a slider bar, but sliding it does not reveal a profile line.

    Since first using FEFLOW v.4.8, I have never seen this feature to work.
  • Thanks!

    maybe it something you will want to add to further versions of FEFLOW  ? ? ?
    it helps when you need to have small time steps but want to avoid mega-files...

    Elad