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-   -   Solving forces & coeffs (https://www.cfd-online.com/Forums/openfoam-solving/101373-solving-forces-coeffs.html)

Astarta May 2, 2012 09:37

Solving forces & coeffs
 
Hello every1!
I`ve troubles with solving forces an coeffs
I use SRFSimpleFoam :

"--> FOAM Warning :
From function void forces::read(const dictionary&)
in file forces/forces.C at line 309
Could not find Uabs, p in database. "

conrtolDict:
" {
type forces
functionObjectLibs ("libforces.so);
patches (MODEL);
pName p;
UName Uabs;
log true;
rhoName rhoInf;
rhoInf 1.225;
CofR (0 0 0);
outputControl timeStep;
outputInterval 1;
}"

Any help will be appreciated
Best regards,
Astarta

colinB May 3, 2012 02:58

Hi,

just a guess from the information you provided:

Code:


patches (MODEL);
pName p;
UName Uabs;

do these three entities contain the name of the patch
you want to calculate the forces on (patch) and the name
of the file specifying the pressure values (pName) and
velocity values (UName)
and are these files located in a folder named 0,
for the problem is:

Code:


Could not find Uabs, p in database

and the question is y? usually this is a naming or storing issue.

I hope I could contribute
regards

Astarta May 4, 2012 05:08

Thanks! It helped, noweverything`s ok!

niran March 9, 2017 08:45

--> FOAM FATAL IO ERROR:
keyword origin is undefined in dictionary "/home/user/OpenFOAM/user-2.4.0/run/work/3_waveflume/system/controlDict.functions.forces"

file: /home/user/OpenFOAM/user-2.4.0/run/work/3_waveflume/system/controlDict.functions.forces from line 10 to line 24.

forces
{
type forces;

functionObjectLibs ( "libforces.so" );

outputControl timeStep;
timeInterval 1;

log yes;

patches ( cylinder );
pName pd;
UName U;
rhoName rhoInf; // Indicates incompressible
log true;
rhoInf 1000;
}

any help please

kera March 9, 2017 09:35

Quote:

Originally Posted by niran (Post 640142)
--> FOAM FATAL IO ERROR:
keyword origin is undefined in dictionary "/home/user/OpenFOAM/user-2.4.0/run/work/3_waveflume/system/controlDict.functions.forces"

file: /home/user/OpenFOAM/user-2.4.0/run/work/3_waveflume/system/controlDict.functions.forces from line 10 to line 24.

forces
{
type forces;

functionObjectLibs ( "libforces.so" );

outputControl timeStep;
timeInterval 1;

log yes;

patches ( cylinder );
pName pd;
UName U;
rhoName rhoInf; // Indicates incompressible
log true;
rhoInf 1000;
}

any help please

centre of rotation is missing in your forces functionObject.

Code:

CofR (0 0 0) // also depends on your case

niran March 9, 2017 10:31

thank you KERA now it is running

CofR required ?
In waves2Foam there is no p file i changed to pd which is available in this solver but unit of both p & pd are not same. Is any problem will come because of this?


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