|July 16, 2013, 06:48||
CFX Oscillating Cylinder FSI Problem
Join Date: Jun 2013
Posts: 3Rep Power: 5
I am trying to do a FSI simulation in CFX using CEL expressions, the problem is of a cylinder mounted on a spring damper system. The expressions used are similar to the ones used in the tutorial with the addition of a damping coefficient term. But unfortunately the amplitude of oscillation predicted by CFX is much higher than the reference values. My CEL expressions are as follows,
m = 1.1e-4 [Kg]
K = 12.012 [N m^-1]
C = 5e-5 [Kg s^-1]
FFlow = force_y@INTERFACE (INTERFACE is the interface between the cylinder and fluid)
MeshVel = areaAve(Mesh Velocity Y)@INTERFACE
YOld = areaAve(Total Mesh Displacement Y)@INTERFACE
tstep = 5e-4 [s]
Numer = (m*YOld)/tstep^2) + (m*MeshVel/tstep) + (C*YOld/tstep) + FFlow
Denom = (m/tstep^2) + (C/tstep) + K
YNew = Numer/Denom
I then use this YNew value to specify the displacement of the mesh at the next time step.
I don't know why this set up doesn't work. If somebody can tell me anything about it, it would be very helpful.
Also can anyone tell me how the Mesh Velocity Y function calculates the mesh velocity? Is it the velocity change from the previous mesh or from the initial mesh?
|July 23, 2013, 16:43||
Join Date: Apr 2009
Posts: 531Rep Power: 13
Check Mesh Velocity Y is giving you something sensible. I saw monitor points for this giving strange values recently.
|Thread||Thread Starter||Forum||Replies||Last Post|
|Ansys 13 CFX problem on LInux Opensuse 11.4||serendipity||CFX||10||August 7, 2012 03:24|
|Oscillating Cylinder in Parallel Flow: Analytical Solution||startingcfd||Main CFD Forum||7||March 23, 2012 06:49|
|Numerical oscillations in CFX with water boiling problem.||michujo||CFX||4||December 16, 2011 10:00|
|CFX Casting problem: Can it be done all in one?||jfasl||CFX||1||September 14, 2010 03:14|
|problem with oscillating cylinder||ammi||FLUENT||0||December 18, 2006 05:06|