CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

Piston motion with time varying experimental data oscillatingFixedValue

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   March 12, 2009, 18:33
Default I am using openfoam 1.4 in cyg
  #1
eno
New Member
 
Sean Bian
Join Date: Mar 2009
Posts: 19
Rep Power: 8
eno is on a distinguished road
I am using openfoam 1.4 in cygwin to solve internal compressible turbulent flow under the motion of a piston. By modifying rhoTurbFoam I can use oscillatingFixedValue in cellMotionUX to define a sinusoidal piston motion Ux = f*(a*sin(2*pi*t)+1). The mesh deforms as expected and the simulation looks reasonable.
Now I want to drive the piston with motions (time varying, no sinusoidal displacement) measured from experiment. How can I do it?
eno is offline   Reply With Quote

Old   March 13, 2009, 03:07
Default Hi, if I remember rightly,
  #2
Member
 
Marco Müller
Join Date: Mar 2009
Location: Germany
Posts: 94
Rep Power: 8
marico is on a distinguished road
Hi,

if I remember rightly, this is not trivial. Maybe you can approximate the values analytically and use groovyBC. I tried just yesterday to apply the "standard piston law of motion" (way over time) and it worked perfect.

Best Regards
Marco
marico is offline   Reply With Quote

Old   March 13, 2009, 16:18
Default Can I just modify the code to
  #3
eno
New Member
 
Sean Bian
Join Date: Mar 2009
Posts: 19
Rep Power: 8
eno is on a distinguished road
Can I just modify the code to read and interpolate the external velocity at where Ux = f*(a*sin(2*pi*t)+1) is executed?
eno is offline   Reply With Quote

Old   March 19, 2009, 11:06
Default
  #4
eno
New Member
 
Sean Bian
Join Date: Mar 2009
Posts: 19
Rep Power: 8
eno is on a distinguished road
dang... it's readily there! just modify cellMotionUx (or other initial files) like:

piston
{
// type oscillatingFixedValue;
// refValue uniform 1.;
// amplitude .2;
// frequency .5;
// value uniform 0;
type timeVaryingUniformFixedValue;
timeDataFileName "pistonVelocity.dat";
value uniform 0;
}
eno is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CFX Piston Motion (CEL) Dante CFX 13 May 31, 2012 08:47
Piston motion with time varying experimental data oscillatingFixedValue eno OpenFOAM Running, Solving & CFD 0 March 12, 2009 18:31
motion of piston wave maker chandra sekhar b Main CFD Forum 0 October 31, 2008 08:06
Piston Motion A Student CD-adapco 0 April 18, 2006 11:36
piston motion Arpan CD-adapco 1 March 9, 2006 08:52


All times are GMT -4. The time now is 00:07.