# How to use rotatingWallVelocity boundary condition

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 June 16, 2012, 08:34 #21 Senior Member     mauricio Join Date: Jun 2011 Posts: 136 Rep Power: 8 hi! have you set the reference axis and origin point properly? i mean.. if ur cylinder is to rotate around its axial axis, this axis should be the reference one and the origin any point on the center of the cylinder base.. if you have those properlly then i guess we'd have to see your case.. post the 0/ folder files plus the constant ones w/o the mesh, if its too big __________________ Best Regards /calim "Elune will grant us the strength"

 June 16, 2012, 09:28 #22 New Member   Bhupesh Verma Join Date: Jun 2012 Location: INDIA Posts: 9 Rep Power: 5 hi... Thanx for ur rply... Now i got my simulation correctly using you code only... I had not deleted the "value" field of "fixedValue" condition..

October 4, 2012, 18:30
#23
Member

ali jafari
Join Date: Sep 2012
Posts: 50
Rep Power: 4
Quote:
 Originally Posted by gpextra Dear colleagues, I am making use of this post to show you a similar problem I have had using rotating walls with OpenFoam. I am a beginner (in OpenFoam) and this is the case: It is a lid-driven cavity problem where the lid is not flat, but a rotating cylinder. The solver was icoFoam from OpenFoam 2.0.0. Conceptually this is exactly the same old 2D lid-driven cavity, but with this slightly different geometry. The internal flow details are unimportant and I will focus only on the wall velocity. This is part of the mesh dictionary to illustrate the very simple geometry: convertToMeters 0.001; vertices ( (0 0 0) // 0 (1 0 0) // 1 (1 1 0) // 2 (0 1 0) // 3 (0 0 1) // 4 (1 0 1) // 5 (1 1 1) // 6 (0 1 1) // 7 ); blocks ( hex (0 1 2 3 4 5 6 7) (20 20 1) simpleGrading (1 1 1) ); edges ( arc 3 2 (0.5 1.5 0) arc 6 7 (0.5 1.5 1) ); The velocity boundary condition for the (rotating) lid is is specified as bump { type rotatingWallVelocity; origin (0.5 1 0); axis (0 0 1); omega 0.001; // a rather small value! } Well, I would expect that the wall absolute velocity was constant, and the x and y-velocities were of sin or cos shaped. But no! The wall velocity profile, shown in the attached figure, has a misbehaving y-velocity component with one full period of a sine (the x-velocity component is not that bad). In fact this is a simplified version of my real problem, where I identified this weird behavior, just to illustrate the essence of the problem with rotating walls. I have also attached a zipped file with all the other relevant files, in case someone wants to run the case. I hope someone can help me with this weirs wall velocity profile. Regrads, G.Paulo.
Hi
I used your case but this error appeared OF 1.5 dev)
Cannot find 'value' entry on patch bump of field U in file "/home/ali/OpenFOAM/ali-1.5-dev/run/rotatingwall/0/U"
which is required to set the values of the generic patch field.
(Actual type rotatingWallVelocity)

Please add the 'value' entry to the write function of the user-defined boundary-condition
or link the boundary-condition into libfoamUtil.so

file: /home/ali/OpenFOAM/ali-1.5-dev/run/rotatingwall/0/U::bump from line 31 to line 34.

From function genericFvPatchField<Type>::genericFvPatchField(con st fvPatch&, const Field<Type>&, const dictionary&)
in file fields/fvPatchFields/basic/generic/genericFvPatchField.C at line 72.

FOAM exiting

also this error occur on other case that include rotatingwallvelocity !!
my OF has a problem ?!

 March 25, 2013, 21:59 #24 Member   Albert Tong Join Date: Dec 2010 Location: Perth, WA, Australia Posts: 74 Blog Entries: 1 Rep Power: 6 Hi Foamers, Hope this thread is still active. I would like to set a time-dependent rotating speed, for instance, t<10, omega=5; t>10, omega=0; Is it possible to do this with rotatingWallVelocity? Many thanks. Regards, Albert

March 26, 2013, 18:03
#25
Senior Member

mauricio
Join Date: Jun 2011
Posts: 136
Rep Power: 8
Quote:
 Originally Posted by tfuwa Hi Foamers, Hope this thread is still active. I would like to set a time-dependent rotating speed, for instance, t<10, omega=5; t>10, omega=0; Is it possible to do this with rotatingWallVelocity? Many thanks. Regards, Albert
hi
im confident u can do that with SwAK4Foam http://openfoamwiki.net/index.php/Contrib/swak4Foam

but check the new type of bc which allows for time dependent BCs.. u might have to insert a table and ur BC should like this
Code:
```type    rotatingWallVelocity
uniformValue     table
(
(0   0.0)
(5  10.0)
);```
first colum time and the other the variable of the bc... check the *.c and *.h file you should find something there .. also read this release http://www.openfoam.org/version2.1.0...conditions.php
i guess u dont need ti use swak4foam

good luck!

im not on my Foam desktop but check for a type of BC which is
__________________
Best Regards
/calim

"Elune will grant us the strength"

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