# Static vs Total Pressure

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

 May 23, 2000, 06:07 Static vs Total Pressure #1 Alfonso Ferrandez Guest   Posts: n/a Dear all, I've found out something that has been driving me mad lately, and I wanted to share it with you, as well as to try and get a solution to the problem. My UDF in Fluent 5.2 requires to know the value of the TOTAL pressure in certain threads in the domain. So far I've been using an average pressure calculated with the F_P() macro. Only today I realised that this macro returns in fact the STATIC pressure and NOT the TOTAL pressure. Obviously with flow acceleration I get drops in STATIC pressure in favour of DYNAMIC pressure. So here's the conundrum for all Fluent Guru's out there: Is there any way at all I can extract the value of the TOTAL pressure instead of the STATIC pressure out of the domain? Thanks in advance to you all! AL P.S. If you want me to post the STATIC pressure calculation routine, let me know. That would be another one for the repository

 May 23, 2000, 08:48 Re: Static vs Total Pressure #2 Sung-Eun Kim Guest   Posts: n/a In FLUENT 5, total pressure is a "derived" quantity (static pressure is a "solution variable). And FLUENT 5 does not store total pressure in the memory. So whenever you need it, you need to compute it. One thing you should keep in mind is that static pressure in FLUENT 5 is a gague pressure. The UDF should look like then: ... real op_press = RP_Get_Real("operating-pressure"); real p_tot; begin_c_loop(c,t) { real Vmag = cellVelocityMagnitude(c,t); p_tot = C_P(c,t)+0.5*C_R(c,t)*Vmag*Vmag+op_press; ... }

 May 23, 2000, 08:53 Re: Static vs Total Pressure #3 Alfonso Ferrandez Guest   Posts: n/a Thanks Kim for such a prompt and complete response! I shall implement your solution straight away. Cheers! AL

 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 auf dem feld FLUENT 17 February 26, 2016 14:04 Gearb0x OpenFOAM Running, Solving & CFD 2 February 28, 2011 22:18 Zou Jianfeng FLUENT 0 October 21, 2008 01:55 Sohail Ahmed Main CFD Forum 0 May 19, 2004 05:43 chong chee nan FLUENT 0 December 29, 2001 06:13

All times are GMT -4. The time now is 17:27.