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

PISO Question

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 2, 2009, 12:01
Default PISO Question
  #1
Senior Member
 
Antonio Martins
Join Date: Mar 2009
Location: Porto, Porto, Portugal
Posts: 112
Rep Power: 17
titio is on a distinguished road
Send a message via MSN to titio Send a message via Skype™ to titio
Hi Foamers,

A small question about the PISO algorithm implemented in icoFoam and other solvers. The fvVectorMatrix UEqn,
defined for the momentum predictor is recalculated in each time step of PISO. Why are the coefficients of this
matrix not set to zero before the new time step? Are all the values of this matrix recalculated and overwrited
in the next time step.

My problem is that I am trying to solve a problem where I have extra tensions besides the newtonian stresses, and
I noticed that a PISO starts well but then it starts to miss behave, in particular giving a completely wrong velocity
profile.

Can be problem be attributted to problems in the calculation of the coefficient matrix or not? Can someone
help me out?

Titio
titio is offline   Reply With Quote

Old   July 6, 2009, 05:33
Default
  #2
Senior Member
 
Henrik Rusche
Join Date: Mar 2009
Location: Wernigerode, Sachsen-Anhalt, Germany
Posts: 281
Rep Power: 18
henrik is on a distinguished road
Titio,

In C++, variables live only up to the next "}".

So, UEqn is created in line 63 and deleted in line 106 of icoFoam.C.

Henrik
henrik is offline   Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
PEqnflux in compressible and incompressible PISO loop dbxmcf OpenFOAM Running, Solving & CFD 3 September 27, 2019 06:13
Unanswered question niklas OpenFOAM 2 July 31, 2013 16:03
Question about PISO kar OpenFOAM Running, Solving & CFD 6 March 10, 2008 09:29
PISO vs. SIMPLE benedikt flurl Main CFD Forum 2 April 14, 2005 06:54
question K.L.Huang Siemens 1 March 29, 2000 04:57


All times are GMT -4. The time now is 19:21.