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-   -   Scripting Fluent, reference values? (https://www.cfd-online.com/Forums/fluent/88134-scripting-fluent-reference-values.html)

Unneoetech May 9, 2011 11:57

Scripting Fluent, reference values?
 
I'm doing research on airfoils and winglets and want to see the lift and drag coefficient curves for different angles of attack. I'm using a script to run a solution from a ready to run case file which adapts the inlet conditions, initializes, solves and saves the data file. Fluent 13 runs on the server so I start it using ssh. Using the nohup command I can let it run overnight (even if I close the ssh connection) and see the output in nohup.out or open the .dat files. All works really well but in post processing I need to open the data file, specify the force vector (different for each angle of attack...), change the reference values (if I changed the velocity) and report on the forces, both for lift, drag and sometimes moment (which is a bit easier off course).
I can report the forces from the script file but If I change the velocity I have to change the reference values in Fluent and I can not find this in the command line options.

Is there a way to let my script to these things? I was trying to do it from a command line in fluent -g but could not find how to do this...

This is an example of my script for two angles of attack:
Code:

rc Airfoil/3D/Fluent_winglet/Wingfinal4.cas o
/define/boundary-conditions/velocity-inlet inlet yes yes no 25.72 no 0 yes no 0.990268 no -0.139173 no 0 no yes 0.1 0.01
/solve/initialize/initialize-flow
/solve/iterate 100000
/file/write-data Airfoil/3D/Fluent_winglet/V25.72AOA-8 o
/report/forces/wall-forces yes 0.139173 0.990268 0 no
/report/forces/wall-forces yes 0.990268 -0.139173 0 no
/report/forces/wall-moments yes 0.25 0 0 0 0 -1 no
rc Airfoil/3D/Fluent_winglet/Wingfinal4.cas o
/define/boundary-conditions/velocity-inlet inlet yes yes no 25.72 no 0 yes no 0.994522 no -0.104528 no 0 no yes 0.1 0.01
/solve/initialize/initialize-flow
/solve/iterate 100000
/file/write-data Airfoil/3D/Fluent_winglet/V25.72AOA-6 o
/report/forces/wall-forces yes 0.104528 0.994522 0 no
/report/forces/wall-forces yes 0.994522 -0.104528 0 no
/report/forces/wall-moments yes 0.25 0 0 0 0 -1 no
exit o

My matlabscript to build the input files:
Code:

clc; clear all; close all
vels=[25.72 30.87 36.01 41.15];%
fid= fopen('script.flin','a');
AOA=[-8 -6 -4 -2 0 2 4 6 8 10 11 12 13];
iter=100000;
tweedried=3;
homefolder='Airfoil/3D/Fluent_winglet/';
casefile='Wingfinal4.cas';
inletname='inlet';
if tweedried==2
    for i=1:length(vels);
        for j=1:length(AOA);
            fprintf(fid,['rc ',homefolder,casefile,' o\n']);
            fprintf(fid,['/define/boundary-conditions/velocity-inlet ',inletname,' yes yes no %g no 0 no %g no %g no yes 0.1 0.01\n'],[vels(i) cos(AOA(j)/360*2*pi) sin(AOA(j)/360*2*pi)]);
            fprintf(fid,'/solve/initialize/initialize-flow\n');
            fprintf(fid,'/solve/iterate %g\n',iter);
            fprintf(fid,['/file/write-data ',homefolder,'V',num2str(vels(i)),'AOA',num2str(AOA(j)),' o\n'],iter);
            fprintf(fid,'/report/forces/wall-forces yes %g %g no\n',[-sin(AOA(j)/360*2*pi) cos(AOA(j)/360*2*pi)]);
            fprintf(fid,'/report/forces/wall-forces yes %g %g no\n',[cos(AOA(j)/360*2*pi) sin(AOA(j)/360*2*pi)]);
            fprintf(fid,'/report/forces/wall-moments yes 0.25 0 0 0 -1 no\n');
        end
    end
else
    for i=1:length(vels);
        for j=1:length(AOA);
            fprintf(fid,['rc ',homefolder,casefile,' o\n']);
            fprintf(fid,['/define/boundary-conditions/velocity-inlet ',inletname,' yes yes no %g no 0 yes no %g no %g no 0 no yes 0.1 0.01\n'],[vels(i) cos(AOA(j)/360*2*pi) sin(AOA(j)/360*2*pi)]);
            fprintf(fid,'/solve/initialize/initialize-flow\n');
            fprintf(fid,'/solve/iterate %g\n',iter);
            fprintf(fid,['/file/write-data ',homefolder,'V',num2str(vels(i)),'AOA',num2str(AOA(j)),' o\n'],iter);
            fprintf(fid,'/report/forces/wall-forces yes %g %g 0 no\n',[-sin(AOA(j)/360*2*pi) cos(AOA(j)/360*2*pi)]);
            fprintf(fid,'/report/forces/wall-forces yes %g %g 0 no\n',[cos(AOA(j)/360*2*pi) sin(AOA(j)/360*2*pi)]);
            fprintf(fid,'/report/forces/wall-moments yes 0.25 0 0 0 0 -1 no\n');
        end
    end 
end
fprintf(fid,'exit o');
fclose(fid);

I run the whole script from a terminal, connected via ssh to the server which has fluent, with:
nohup fluent 3d -t 4 -g -i Airfoil/3D/Fluent_winglet/script.flin &
Edit:
I found a way to edit the reference values via the commandline. It is under /report/reference-values...

Fabio88 October 14, 2016 05:02

Hi,

I read your post and I think it can be useful for me since I would liek to start use scripting to launch my fluent simulations instead of open and running all the cases one by one.
Do you have any suggestion about how to start? like some manuals or posts that you think can be useful?

Thanks a lot,

Fabio


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