# congence???

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 LinkBack Thread Tools Display Modes
 June 13, 2006, 01:58 congence??? #1 prayskyer Guest   Posts: n/a i did some a computation! i chose air(idea gas) as fluid, and reference pressure=14atm;energy model----total energy;k-e model;intial condition=automatic BC:inlet---mass rate;total tempreture=1200K; outlet----reletive pressure=-600000Pa; it never congence,but when i turn outlet's reletive pressure to 0Pa,it congence,it that 14atm have some problem?if not,where can i modify them? how this could happen,and what can i do? thanks in advance!!!

 June 13, 2006, 02:53 Re: congence??? #2 Fred Guest   Posts: n/a Do you mean convergence? A negative pressure is not very well chosen because there is no negative pressure in the universe. Under domain you can set the reference pressure to 0 atm and then calculate or set every pressure as it is in real.

 June 13, 2006, 03:28 Re: congence??? #3 prayskyer Guest   Posts: n/a but 14atm-600000Pa=800000Pa,it's a positive value! if i set 0 for reference pressure,then the outlet's pressure will really become negative value (0--600000Pa=-600000Pa)

 June 13, 2006, 15:15 Re: congence??? #4 Fred Guest   Posts: n/a Then set the outlet to 8 atm. Where is the problem?

 June 13, 2006, 20:50 Re: congence??? #5 prayskyer Guest   Posts: n/a haha,i found it!the inlet is subsonic,but outlet is supersonic,i set them wrong! so this flow from subsonic area into supersonic area,is some suggestions i can concern? thanks all of u

 June 13, 2006, 21:55 Re: congence??? #6 prayskyer Guest   Posts: n/a i am wrong again!it's still subsonic! the problem still on!!!

 June 14, 2006, 06:45 Re: congence??? #7 Fred Guest   Posts: n/a YOu can try to change the outlet to an opening. This is more stable then a subsonic outlet.

 June 14, 2006, 07:28 Re: congence??? #8 prayskyer Guest   Posts: n/a i try!but it seems not that problem there! seems that outlet's relative pressure -600000, IN CFX,can i put negative value like -600000 there?

 June 14, 2006, 10:48 Re: congence??? #9 Fred Guest   Posts: n/a i dont see the benefit in doing this. why do you do this? why not 0atm and 8 atm?

 June 14, 2006, 20:08 Re: congence??? #10 prayskyer Guest   Posts: n/a 0atm and 8atm can't congence either! i try once! i don't know why? how long can i solve this problem,help me! thanks

 June 14, 2006, 20:12 Re: congence??? #11 prayskyer Guest   Posts: n/a could anyone help me! prayskyer@yahoo.com.cn this is my e-mail!i can send this to u! thanks a lot!

 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 prayskyer CFX 1 June 12, 2006 02:09

All times are GMT -4. The time now is 14:38.

 Contact Us - CFD Online - Top