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

Expert Parameter for compressible transient

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

Reply
 
LinkBack Thread Tools Display Modes
Old   November 2, 2005, 20:28
Default Expert Parameter for compressible transient
  #1
ioannis
Guest
 
Posts: n/a
Hello,

I am simulating the compression stroke of an internal combustion engine and I have problems when setting the expert parameter "pref for compressible transient" to true.

The working fluid is air ideal gas and then I plan to inject ch4, in order to see how the mixture homogeneity evolves with the piston motion.

The solver gave me the notice that I should set the expert parameter: "pref for compressible transient" to true. I set this parameter to true and then came another error:

+--------------------------------------------------------------------+ | Reference Pressure Information | +--------------------------------------------------------------------+

Domain Group: Cyl

Pressure has not been set at any boundary conditions.

The pressure will be set to 0.00000E+00 at the following location:

Domain : Cyl

Node : 1 (equation 1)

Coordinates : ( 2.56243E-02,-1.44915E-02, 1.99480E-02).

I have already had a complete run with the default value of the expert parameter: "pref for compressible transient" set to false. Does this have a big influence on my results? What does this parameter actually do?

I have read in a previous post that for Tascflow one should set the LCHECKP to false, but this doesnt work for CFX5.7.1.

Any suggestions on getting it to work?

Has anybody worked with this problem before? Any tips for doing such a transient simulation? Are there any best practices? Timestepping? Grid generation?Yplus?

I was just wondering if I could see any difference in the results by using a unstructured grid with tetras.

Thank you very much, Ioannis
  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
Transient Parameter Variation Milanowski FLUENT 3 April 22, 2010 12:37
Expert parameter to stop the fluid flow simulation KK CFX 1 February 25, 2008 17:29
MAxium residual...confusion with expert parameter KK CFX 3 February 8, 2008 11:47
asking for a few expert parameter for rotarywing charles CFX 4 November 3, 2006 15:15
Units for expert parameter "tbulk for htc" cfx_user CFX 0 October 30, 2005 09:09


All times are GMT -4. The time now is 22:22.