[Dezzo]

Dear all,
this is my first post on the forum, so please be patient if I made silly questions, and please be patient also if this is not the correct place…

Going to the topic, I’m using rhoPimpleFoam to solve a steady case and I would like to modify the Courant number (in order to reduce the computational time) automatically during the simulation, for example in a sinusoidal way, since I’m only interested on final values (p, T, U, rho).

I looked for something similar in the forum, I found the some this for example:
how to get current time as scalar?

So I tried to wrote something like:

[c]aMax 10; //amplitude
maxCo #eval "($aMax+0.5)-(($aMax)*(cos(2*3.14159*$runTime.value()/$endTime)))"; // sine wave with min value 0.5 at start and at endTime=0.005
[/c]

I got
[c]FOAM FATAL ERROR
Syntax error in expression at position:42
<<<<
(10.00000+1)-((10.00000)*(cos(2*3.14159*/0.005000)))
^^^^ near here[/c]

I also tried to add:

[c]scalar t=time().value()[/c]

instead of runTime.value()

I also tried many little modifications but I was not able to make it to work correctly.


Can someone show me the right way?
Many thanks!

[Dezzo]

I was able to manage the issue in a pragmatic way using the function object timeActivatedFileUpdate:

fileUpdate
    {
        type            timeActivatedFileUpdate;
        libs (utilityFunctionObjects);
        writeControl   timeStep;
        writeInterval  1;
        fileToUpdate    "$FOAM_CASE/system/controlDict";
        timeVsFile
        (
            (-1    "$FOAM_CASE/system/controlDict_1")
            (#eval "($endTime*0.02)"    "$FOAM_CASE/system/controlDict_2")
            (#eval "($endTime*0.05)"    "$FOAM_CASE/system/controlDict_5")
            (#eval "($endTime*0.95)"    "$FOAM_CASE/system/controlDict_2")
            (#eval "($endTime*0.98)"    "$FOAM_CASE/system/controlDict_1")
        );
    }

Varing the Courant number in each controlDict file.

But I’m still looking for something more elegant.

Thanks