How to get the pressure and pressure loss in fluent while using periodic

winnawinna · January 4, 2011, 23:57

boundary condition?
Streamwisely set the flow inlet and flow outlet as a pair of periodic boundary, and now I want to get the pressure loss between the flow inlet and the flow outlet. I tried two ways:
1. Cut surfaces in the position of inlet and outlet, and get the total pressure of both. (the value between the two surfaces are almost the same)
2. Find the pressure gradient in b.c.->periodic conditions, and multiply the length.
The results of the two ways are totally different. Which one is right?

laurentb · May 6, 2011, 04:44

I've got the same problem. Does anybody can help us ?
Pressure field are very strange with periodic condition.
The second solution is described in fluent doc :

" 9.2.2 User Inputs for the Pressure-Based Solver ....

Note that the current value of [IMG]file:///C:/PROGRA%7E1/ANSYSI%7E1/v121/fluent/fluent12.1.4/help/html/ug/img2766.gif[/IMG] will be displayed in this field if you have performed any calculations. To update the Pressure Gradient field with the current value at any time, click on the Update button.
"

January 4, 2011, 23:57	How to get the pressure and pressure loss in fluent while using periodic	#1
winnawinna New Member wanchaoyi Join Date: Dec 2010 Posts: 2 Rep Power: 0	boundary condition? Streamwisely set the flow inlet and flow outlet as a pair of periodic boundary, and now I want to get the pressure loss between the flow inlet and the flow outlet. I tried two ways: 1. Cut surfaces in the position of inlet and outlet, and get the total pressure of both. (the value between the two surfaces are almost the same) 2. Find the pressure gradient in b.c.->periodic conditions, and multiply the length. The results of the two ways are totally different. Which one is right?

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May 6, 2011, 04:44		#2
laurentb Member Laurent B Join Date: Jun 2009 Location: Lille, FRANCE Posts: 70 Rep Power: 17	I've got the same problem. Does anybody can help us ? Pressure field are very strange with periodic condition. The second solution is described in fluent doc : " 9.2.2 User Inputs for the Pressure-Based Solver .... Note that the current value of [IMG]file:///C:/PROGRA%7E1/ANSYSI%7E1/v121/fluent/fluent12.1.4/help/html/ug/img2766.gif[/IMG] will be displayed in this field if you have performed any calculations. To update the Pressure Gradient field with the current value at any time, click on the Update button. "