CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Main CFD Forum

PISO - new questions

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

Reply
 
LinkBack Thread Tools Display Modes
Old   May 7, 2005, 12:02
Default PISO - new questions
  #1
Benedikt Flurl
Guest
 
Posts: n/a
This is already the third time that I am asking about PISO, but strange things are happening and perhaps anybody can help me: I implemented the PISO and it is running but it doesn't hold what for example Issa is promising: -In steady state cases I can realy calculate very fast, sometimes four times as fast as SIMPLE (then also iteratively in PISO), but in unsteady cases (for example Karman Vortex Street) I cannot see advantages. Some Information about my Program: -I used for the second Pressure Correction Equation the same coefficients as in the first one. They contain the Neumann-Boundary-Conditions for all Boundaries. Have I to change them in any way? -In the unsteady cases Issa shows, it is possible to run PISO without Iteration for small time steps. What is SMALL? How can I see, that the approximated solution is good, what can I use as Residuum (the normally used residuum is remaining high...) -I do not use underrelaxation for Momentum Equations and no underrelaxation Pressure Correction.

Thank you all for your help, I hope anybody understands my problems, it's difficult to formulate them, and I am a CFD beginner. Greatings, Benni!
  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
PISO Details Dr B.M. Smith (Smith) OpenFOAM Running, Solving & CFD 17 November 17, 2009 12:31
Development of a Low mach PISO solver nishant_hull OpenFOAM Programming & Development 0 August 25, 2009 12:48
PISO Questions titio OpenFOAM Running, Solving & CFD 0 July 2, 2009 12:00
SIMPLE and PISO Aditya Main CFD Forum 5 April 1, 2006 18:52
PISO vs. SIMPLE benedikt flurl Main CFD Forum 2 April 14, 2005 06:54


All times are GMT -4. The time now is 21:59.