• Re: Set maximum CPU/core usage for FEFLOW model simulation

    As a complement of information, could you give us some details about the command line flag 'threads'?
    -threads <num>|single : Number of worker threads

    Does it limit the number of CPUs used for matrix assembly as well as matrix solving?
    (If so, that would be a nice exec. flag to use within FePEST to optimize parallel model runs without overloading CPUs with competing threads...)


  • Re: How to find the release notes for most recent FEFLOW updates?

    Thanks for your reply, Peter.
    Ok. Great! We'll be patient.
    (If you're still working on the design of the change log, I may suggest one I like: http://www.tracker-software.com/PDFXE_history.html)


  • Re: How to find the release notes for most recent FEFLOW updates?

    Thanks. But as an update to your previous answer, could you tell us where we can find up-to-date detailed release notes for FEFLOW 7.0?
    I know there is that web page (MIKE 2016, Release Notes, FEFLOW) but "No fixed issues" does not sound detailed enough, considering at least 1 patch was released recently.
    The aim of my request is to satisfy the curiosity of users who wish to know what has changed or improved from a release to the next.
    Thanks in advance!

  • How to find the release notes for most recent FEFLOW updates?

    Dear FEFLOW team, I'd like to know how I can find the release notes documentation that we could previously get simply by clicking on the hyperlink in the Update Dialog that pops up when an update is available. Because of some important changes in the web site structure I suppose, this link does not work anymore... and I cannot find the list of bugs that were fixed in last updates (i.e. the Release Notes, e.g. for FEFLOW 6.2 p9). Could you make release notes easier to find? For advanced users, this is so interesting to know what was improved in the engine or GUI of an important software like FEFLOW.


  • How to use the nonlinear dispersion relation correctly?


    I'm using FEFLOW to simulate coupled flow & mass&heat transport, with contrasting concentration values: at the top boundary (which corresponds to the sea bottom), a fixed (but flux-constrained) seawater (35 g/L) conc. is assigned, whereas the aquifer initial concentration is around 0 g/L. Density ratio was set to an appropriate value of 0.027.

    I've read a bit about the non-Fickian dispersion type in FEFLOW offline help and in the FEFLOW Book, but I still don't understand how to define the value of the model parameter "Nonlinear dispersion" with its strange units (m2*s/kg). Can you explain me how to benefit from this advanced option (Nonlinear dispersion) within FEFLOW by putting good values for the new parameter? Thanks.

    For those who are not familiar with this option, here is a short citation from FEFLOW help (in "Transport Settings"):
    "Dispersion type: Besides the standard linear Fickian Bear-Scheidegger dispersion, FEFLOW supports a nonlinear dispersion relation. The nonlinear dispersion has shown to lead to more accurate results for density-dependent simulations with high-concentration gradients (brine transport)."
  • Re: Ttime-series and current expression boundary condition

    Thanks for your ideas. But finally, I've decided to learn to write IFM plugins for this kind of density-dependent saltwater transport problem. And it worked well. It is still work in progress, but when the plugin reaches maturity, I may share it with the FEFLOW community. I found it pleasant, actually, to develop a plugin in the Microsoft Visual Studio Express environment, with the IFM-related documentation from FEFLOW help. This offers much more flexibility than the FEFLOW interface does.

    A suggestion for the FEFLOW developers' team: If only expressions could be used to define boundary conditions (or even material properties) that depend on time or other variable, I think we would be able to run many complex models without having to develop problem-specific plugins. Expressions could be created the same way Time Series are; then, the user would associate an expression ID to a node or element. In other words, a parameter would be defined by either A) a constant value, B) a time-dependent value from a time series, C) an expression that is recomputed before or after each time step. Doesn't that sound good?

    Thanks again for your replies. Bye.

  • How to get Problem Settings' reference values in a plugin?

    Hello. I would like to get the Cs (C_s; maximum concentration) reference value in my plugin, but I found no Ifm... function to do so. Is there a way?
  • Re: Ttime-series and current expression boundary condition

    I, also, would like to assign time-dependent b.c.'s to nodes using the Expression Editor, in a Vertical, planar model for simulation of coupled flow and mass transport. The thing is, the Expression Editor allows a user to write a time-dependent expression e.g. "Current = TS.1 @(Time )", but when I click on the Assign button of the Editor toolbar, it assigns a constant value at the selected nodes (the value is the evaluation of my expression at current time).

    The problem is, this is not just about constraints. I need time-dep. expressions because the values I want to apply totally depend on time series. Specifically, I have a time series describing the sea level and I want to apply a typical seawater salt concentration if sea level is above ground, and a freshwater concentration otherwise. The expression would look like (c in mg/L):
    Current = {
    35000 if TS.1 @(Time ) > y_local
    100 otherwise

    Similarly, I need an expression for hydraulic-head BC's* **:
    Current = {
    TS.1 @(Time ) if TS.1 @(Time ) > y_local
    y_local otherwise

    *this expression is equivalent to min(TS.1@(Time), y_local), but I found no expr. function for min(...)
    **moreover, I found no hydraulic-head constraint for the fluid flow h-head b.c., though it exists for mass transport mass-conc. b.c.

    In the above expression, note that the condition is time-dependent AND spatially-dependent. That's why I want to use expressions instead of multiple time series: it would requires hundreds, thousands of TS!

    So, how can I apply such time-dependent b.c.'s in FEFLOW?

    My question is probably addressed to the FEFLOW team, but if as a user of the software you know a way to do this, your help would be precious!

    Thanks in advance.


  • Applying a recharge BC on top of a 2D vertical (cross-sectional) model


    I want to build a numerical version of my 2D cross-sectional conceptual model for groundwater flow only (no transport at this time). FEFLOW 6.0 has an option to activate such type of projection, in Problem Settings. But I don't find appropriate Boundary Condition parameters to apply recharge on top of my model.

    The problem is, I think, that the definition of the top surface of the model differs from 3D projections. Actually, I would need a way to apply a "linear" recharge on the upper linear boundary of my model (~ the XZ plane) ... rather than on the cross-sectional XY plane. Why is the "In/outflow on top" flow property removed when using a 2D vertical model? Wouldn't it be a simpler (and more coherent) way to apply recharge than imposing a 2nd type fluid-flux BC?

    The main issue using such fluid-flux BC (e.g. a uniform downward recharge flux) is that it prevents the solver from inferring discharge zones along the top of the model. As a consequence, I think that using 2nd type BC for recharge is inappropriate for the upper limit of a flow model. But what can I use instead?

    In short, I need your help to demystify recharge definition within a 2D-vertical model (please consider a simple case with steady-state uniform recharge).

    Looking forward to reading from you!

    PhD student, Quebec, Canada.