# CFD-ACE compressible flow convergence problem

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

 October 12, 2009, 10:48 CFD-ACE compressible flow convergence problem #1 New Member   Delphine Laboureur Join Date: Oct 2009 Location: Brussels Posts: 3 Rep Power: 9 Hello everybody! I would like to simulate a reservoir of water & air, heated from outside and observe the natural convection due to density change with temperature. I use for that CFD-ACE But I have convergence problem: If I set the air & water density as constant, it converges, but I will never see natural convection If I set the air compressible (ideal gas law) & the water constant, it converges. But the water is just a first step before a simulation with propane, so I would like to make it compressible If I set the air with constant density & the water with piecewire linear with T, it does not converge. ==> all the other parameters are kept similar... So the problem is obviously coming from the compressibility of the water... Did anyone already try to simulate natural convection with 1 liquid and 1 gas on top of each other? Thanks a lot in advance!

 October 21, 2009, 05:50 #2 New Member   Delphine Laboureur Join Date: Oct 2009 Location: Brussels Posts: 3 Rep Power: 9 Hello! I know that nobody repplied, but, just in case someone could be interested by this question: the problem is that CFD-ACE does not support a solution with 2 phases with changing density, especially because of a parameter called "reference density". Therefore, the best is to set the reference density to the one of the liquid, and for the gas, add a flow source as a subroutine, that is linked to convection: like g*(rho - rho_ref)*V I still need to implement this subroutine because I never did it, so if one of you already implemented a USOURCE, please let me know!

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Jas Main CFD Forum 10 March 30, 2013 13:26 Balraj Main CFD Forum 3 December 9, 2004 01:24 John C. Chien Main CFD Forum 36 January 24, 2001 22:10 ram Main CFD Forum 5 June 17, 2000 21:31 Mihai ARGHIR Main CFD Forum 0 April 7, 2000 04:58

All times are GMT -4. The time now is 03:10.