# outlet static pressure of a duct flow

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

 December 17, 2007, 10:24 outlet static pressure of a duct flow #1 anhalimi Guest   Posts: n/a Dear all, Shld the outlet static pressure for a duct flow be zero?

 December 17, 2007, 10:27 Re: outlet static pressure of a duct flow #2 ag Guest   Posts: n/a Only if you are flowing into a vacuum, or you have chosen a non-dimensionalization that results in zero non-dimensional pressure at that value of exit pressure.

 December 17, 2007, 14:11 Re: outlet static pressure of a duct flow #3 Barry Guest   Posts: n/a Hi, I have a similar question about the pressure BC. For an incompressible flow, can I arbitrarily set a static pressure value for the pressure outlet? Does the value I set affect the modelling result? Regards, Barry

 December 18, 2007, 04:38 Re: outlet static pressure of a duct flow #4 Mayur Guest   Posts: n/a What is ur inlet condition? If it is vel. inlet then value of static pr. for incomp. flow will not have any effect on the flow(except for pr. values)

 December 18, 2007, 06:07 Re: outlet static pressure of a duct flow #5 anhalimi Guest   Posts: n/a or you have chosen a non-dimensionalization that results in zero non-dimensional pressure at that value of exit pressure. You mean taking the taking the absolute pressure as 0? as in just measuring the gauge pressure? or am i understanding this wrong

 December 18, 2007, 09:59 Re: outlet static pressure of a duct flow #6 ag Guest   Posts: n/a If you are computing gage pressure then zero may be a valid value. Then your nondimensionalization would look something like p_non = (p - p_baseline)/p_ref where p_ref is the pressure used to non-dimensionalize the pressure variables and p_baseline is whatever baseline pressure you are computing gage pressure relative to. But absolute static pressure should not be zero, unless as noted above you are expanding into a perfect vacuum.

 December 19, 2007, 01:32 Re: outlet static pressure of a duct flow #7 Barry Guest   Posts: n/a Could you please explain why the value of static pr. for incomp. flow will not have any effect on the flow if using velocity inlet BC? Thanks, Barry

 December 19, 2007, 07:28 Re: outlet static pressure of a duct flow #8 Mayur Guest   Posts: n/a Is simple... for incomp. flows pr. enters the equation as only delta P ... so whatever be the absolute value the diffenence will remain the same and flow velocity will decide the pressure gradient... plz go through the analytical soultion of a pipe flow for a laminar case.

 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 jennz CFX 4 February 11, 2014 04:29 saii CFX 2 September 18, 2009 08:07 jpo FLUENT 0 June 22, 2009 12:53 Amit Roghs CFX 1 June 16, 2008 21:51 Miry CFX 0 September 16, 2007 18:14

All times are GMT -4. The time now is 09:53.