pressure not uniform although velocity is uniform at the inlet

swati_mohanty · January 11, 2011, 04:25

Dear all,

I specify the inlet velocity for a multiphase system ( one liquid and two granular solids) but when I simulate I find that the pressure is not uniform across the cross-section of the inlet. Could anybody say why is it so.

thanx

sm

Skabirian · March 6, 2016, 03:58

I have the same problem
can anybody help?

LuckyTran · March 6, 2016, 10:07

If you have a viscous flow, pressure does not have to be uniform and in general is not uniform. If you have a uniform velocity inlet it is unlikely to be uniform.

Skabirian · March 7, 2016, 03:35

I want to calculate CP on the airfoil
reference pressure in pressure at infinity
if its changed, CP changed too.
is this correct?

LuckyTran · March 7, 2016, 07:50

The reference pressure is part of the definition of Cp. Meaning it is defined as soon as you have chosen a particular definition for Cp.

But, the reference pressure is usually the dynamic pressure.

Skabirian · March 7, 2016, 08:46

so, if i want to plot cp ,what will be the pressure (pa) in reference values ?

LuckyTran · March 7, 2016, 12:57

How do you define Cp? The reference pressure is there.

Are you asking what is the definition of Cp?

Skabirian · March 8, 2016, 00:19

p-p(inf)/q(inf)
p(inf) is defined in reference pressure and is changed during the solution because of velocity inlet BC.

January 11, 2011, 04:25	pressure not uniform although velocity is uniform at the inlet	#1
swati_mohanty New Member sm Join Date: Jun 2009 Posts: 15 Rep Power: 16	Dear all, I specify the inlet velocity for a multiphase system ( one liquid and two granular solids) but when I simulate I find that the pressure is not uniform across the cross-section of the inlet. Could anybody say why is it so. thanx sm Skabirian likes this.

March 6, 2016, 10:07		#3
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	If you have a viscous flow, pressure does not have to be uniform and in general is not uniform. If you have a uniform velocity inlet it is unlikely to be uniform. Skabirian likes this.

March 7, 2016, 07:50		#5
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	The reference pressure is part of the definition of Cp. Meaning it is defined as soon as you have chosen a particular definition for Cp. But, the reference pressure is usually the dynamic pressure. Skabirian likes this.

March 7, 2016, 12:57		#7
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	How do you define Cp? The reference pressure is there. Are you asking what is the definition of Cp? Skabirian likes this.

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March 6, 2016, 03:58		#2
Skabirian New Member Siavash Join Date: Nov 2013 Posts: 20 Rep Power: 12	I have the same problem can anybody help?

March 7, 2016, 03:35		#4
Skabirian New Member Siavash Join Date: Nov 2013 Posts: 20 Rep Power: 12	I want to calculate CP on the airfoil reference pressure in pressure at infinity if its changed, CP changed too. is this correct?

March 7, 2016, 08:46		#6
Skabirian New Member Siavash Join Date: Nov 2013 Posts: 20 Rep Power: 12	so, if i want to plot cp ,what will be the pressure (pa) in reference values ?

March 8, 2016, 00:19		#8
Skabirian New Member Siavash Join Date: Nov 2013 Posts: 20 Rep Power: 12	p-p(inf)/q(inf) p(inf) is defined in reference pressure and is changed during the solution because of velocity inlet BC.