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-   -   Generating a parabolic Profile with groovyBC (http://www.cfd-online.com/Forums/openfoam-pre-processing/74210-generating-parabolic-profile-groovybc.html)

erklaerbaer March 26, 2010 12:29

Generating a parabolic Profile with groovyBC
 
Hi,

How can i generate a parabolic velocity profile with groovyBC?
The entry in the openfoamwiki isnt really helpful. The example "parabolic inlet condition that pulsates " generates an error and i cant find any "real" documentation. If someone could point me to the solution i would be really grateful.

erklaerbaer March 27, 2010 06:47

I managed to get a parabolic profile with

Code:

variables "w=0.00005;m=3;n=2;Umax=1*(m+1)*(n+1)/m/n;c=pos().y-w;d=pos().z-w;a=pow((c/w),2);b=pow((d/w),2);speed=Umax*(1-a)*(1-b);";
valueExpression    "vector (speed, 0, 0)";

in my starting file for U but i have two problems.
pow() does not accecpt non integer values for the exponent like pow(a,1.5) is this a "normal" behaviour?
and
i need some function to get the distance from a point like
distance = pos().z-w now this will result in an negative value if pos().z <w which "should" be positive, i tried abs() but it seems its not implemented and i tried something like sqr(pow(pos().z-w,2)) which doesnt work either.

has anybody an idea?
thanks

sega March 27, 2010 09:14

Quote:

Originally Posted by erklaerbaer (Post 251943)
I managed to get a parabolic profile with

Code:

variables "w=0.00005;m=3;n=2;Umax=1*(m+1)*(n+1)/m/n;c=pos().y-w;d=pos().z-w;a=pow((c/w),2);b=pow((d/w),2);speed=Umax*(1-a)*(1-b);";
valueExpression    "vector (speed, 0, 0)";

in my starting file for U but i have two problems.
pow() does not accecpt non integer values for the exponent like pow(a,1.5) is this a "normal" behaviour?
and
i need some function to get the distance from a point like
distance = pos().z-w now this will result in an negative value if pos().z <w which "should" be positive, i tried abs() but it seems its not implemented and i tried something like sqr(pow(pos().z-w,2)) which doesnt work either.

has anybody an idea?
thanks

Strange, pow() should be able to deal with floating point exponents ...

gschaider March 29, 2010 14:31

Quote:

Originally Posted by erklaerbaer (Post 251943)
I managed to get a parabolic profile with

Code:

variables "w=0.00005;m=3;n=2;Umax=1*(m+1)*(n+1)/m/n;c=pos().y-w;d=pos().z-w;a=pow((c/w),2);b=pow((d/w),2);speed=Umax*(1-a)*(1-b);";
valueExpression    "vector (speed, 0, 0)";

in my starting file for U but i have two problems.
pow() does not accecpt non integer values for the exponent like pow(a,1.5) is this a "normal" behaviour?
and
i need some function to get the distance from a point like
distance = pos().z-w now this will result in an negative value if pos().z <w which "should" be positive, i tried abs() but it seems its not implemented and i tried something like sqr(pow(pos().z-w,2)) which doesnt work either.

has anybody an idea?
thanks

According to the grammar file power should work with any scalar-constant as an exponent. It doesn't work with expressions. So something like pow(p,T) or even pow(p,3./2) are NOT possible. What is the expression that is not working for you and what is the error message?

Bernhard

erklaerbaer April 7, 2010 15:42

Sorry for answering so late; I solved the problem another way.
I think (I did and learned a lot inf and of OpenFOAM the last days) I just missused the Expression.

Chrisi1984 June 4, 2010 15:18

groovyBC
 
Hi,

Can someone tell me how I can use groovyBC?

I read the article in OpenFoamWiki http://openfoamwiki.net/index.php/Co...rds_of_warning,

but I do not understand this part:

1.2 Pre-requisites

To compile this utility Bison has to be installed. The compilation is known to work with version 2.4.1. It may probably work with older versions. Check with
bison -V
on the command line before trying to compile it and report the version number when reporting a problem.
2 Usage

2.1 Compilation and installation

Just do
wmake libso
in the directory of the sources. The library will be compiled and installed in a place (%FOAM_USER_LIBBIN) where it is usable





I installed bison 2.4.1 like it is written in the install-file:


./configure
make

make install


where do I now have to write "wmake libso"? What means "in the directory of sources"?


Best Regards


Chrisi

erklaerbaer June 6, 2010 03:54

Hi Chrisi,

you have to type "wmake libso" in the directory of groovyBC. The directory "make" should be in that directory where to type "wmake libso".

--

Wenn du wmake eintippst sucht das Skript nach dem Ordner Make und dort nach den Steuerdateien, deswegen musst dein aktuelles Arbeitsverzeichnis Der Ordner sein wo der Ordner "make" drinliegt.

Chrisi1984 June 6, 2010 11:59

Thank you,

I tried to do so but, I have a problem in compiling groovyBC. I am using OF 1.6.x.

I have bison (GNU Bison) 2.4.1 and flex 2.5.35.

I copied all the files of groovyBC from here https://openfoam-extend.svn.sourcefo...ries/groovyBC/.
and put it into my run folder. When I compile it I get the following error:

root@chrisilinux:~/OpenFOAM/OpenFOAM-1.6.x/lib/linuxGccDPOpt/groovyBC# wmake libso
wmakeLnInclude: linking include files to ./lnInclude
make: *** Keine Regel vorhanden, um das Target »PatchValueExpressionDriver.dep«,
benötigt von »Make/linuxGccDPOpt/dependencies«, zu erstellen. Schluss.
root@chrisilinux:~/OpenFOAM/OpenFOAM-1.6.x/lib/linuxGccDPOpt/groovyBC#

I yet tried compiling with out coomented groovyBCPointPatchFields.C, but it did not help.

Can you help me compilling groovyBC?

Thanks in advance.

Regards
Chrisi

erklaerbaer June 6, 2010 12:54

okay ähm.
You ned to install "svn" if it isnt already there.
Then go to a location of your choice, eg run/user_apps or whatever and paste the following line in the console
and hit Enter, svn will then download all files you ned.

After svn did its job there should be a ne folder, go with the shell to the appropirate folder (where there is a subfolder "make") and enter
"wclean" and than "wmake libso". Should work :D
If there comes an error just post it here.

Currently i have no OpenFOAM installed (or any linux) but i survived installing groovyBC ;)

Chrisi1984 June 6, 2010 14:51

Thank you erklaerbaer!!

Vielen Dank!!

Dann kann ich jetzt mal versuchen damit zu arbeiten.

Now I can use groovyBC!!

Regards
Chrisi


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