The meaning and use of pRefCell and pRefValue

jf115009 · September 25, 2013, 06:00

hello everyone
I am a new user for OF.During the process,I have encountered many questions,but now I have a touchy question. who can explain the meaning and use of pRefCell and pRefValue ? It's better give me some advice about learning OF for a new user.

Thanks

haakon · September 25, 2013, 10:58

http://www.cfd-online.com/Forums/ope...tml#post187268

http://www.openfoam.org/docs/user/fv...-1250004.5.3.1

To state it simple, and to avoid creating a post with only two links:
Imagine an incompressible case where all the boundaries have a zero-gradient pressure condition. What is the pressure inside the domain? Impossible to calculate. The equation system of such a case is thus ill-posed, and we need some more information to calculate the answer. Therefore we select pRefCell and set the pressure in that cell to pRefValue. Then we can solve the system.

Remember that the pressure in an incompressible simulation is somewhat strange, as it is more like a driving force than a physical quantity, as only the relative differences have any meaning.

September 25, 2013, 06:00	The meaning and use of pRefCell and pRefValue	#1
jf115009 New Member jiangfeng Join Date: Sep 2013 Posts: 1 Rep Power: 0	hello everyone I am a new user for OF.During the process,I have encountered many questions,but now I have a touchy question. who can explain the meaning and use of pRefCell and pRefValue ? It's better give me some advice about learning OF for a new user. Thanks

September 25, 2013, 10:58		#2
haakon Senior Member Join Date: Dec 2011 Posts: 111 Rep Power: 19	http://www.cfd-online.com/Forums/ope...tml#post187268 http://www.openfoam.org/docs/user/fv...-1250004.5.3.1 To state it simple, and to avoid creating a post with only two links: Imagine an incompressible case where all the boundaries have a zero-gradient pressure condition. What is the pressure inside the domain? Impossible to calculate. The equation system of such a case is thus ill-posed, and we need some more information to calculate the answer. Therefore we select pRefCell and set the pressure in that cell to pRefValue. Then we can solve the system. Remember that the pressure in an incompressible simulation is somewhat strange, as it is more like a driving force than a physical quantity, as only the relative differences have any meaning. sharonyue, hogsonik, dela and 1 others like this.