MassflowAve & areaAve in cfx

az_f · May 21, 2009, 01:24

Hi All,
I want to calculate the total pressure difference at inlet , outlet and mid plane of one tube with blood flow. I used areAve(total pressure )@inlet and... but I don't the results calculated by massflowAve is different with AreaAve and which one is more accurate?

Any idea?

Thanks

pantarei83 · May 21, 2009, 06:26

The two values are very different? If you considered the fluid incompressible they must be similar. Otherwise I think mass flow ave is better.

ghorrocks · May 21, 2009, 19:27

Hi

The massflowAve is a mass weighted average. This is best for things which are related to mass, such as species concentrations, volume fractions, temperature. The areaAve is an area weighted average. This is best for things which are area functions, like pressure. So for pressure I would use the areaAve pressure to calculate the inlet and outlet pressures.

Glenn Horrocks

LKF · May 22, 2009, 13:40

I think this link offers a fairly good explanation of the difference between the two averaging methods.

http://www.cfd-online.com/Forums/cfx...a-average.html

May 21, 2009, 01:24	MassflowAve & areaAve in cfx	#1
az_f Member Join Date: Mar 2009 Posts: 48 Rep Power: 17	Hi All, I want to calculate the total pressure difference at inlet , outlet and mid plane of one tube with blood flow. I used areAve(total pressure )@inlet and... but I don't the results calculated by massflowAve is different with AreaAve and which one is more accurate? Any idea? Thanks

May 21, 2009, 06:26	High diffrence?	#2
pantarei83 New Member Antonio P. Join Date: Mar 2009 Posts: 10 Rep Power: 17	The two values are very different? If you considered the fluid incompressible they must be similar. Otherwise I think mass flow ave is better.

May 21, 2009, 19:27		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Hi The massflowAve is a mass weighted average. This is best for things which are related to mass, such as species concentrations, volume fractions, temperature. The areaAve is an area weighted average. This is best for things which are area functions, like pressure. So for pressure I would use the areaAve pressure to calculate the inlet and outlet pressures. Glenn Horrocks jaavga1986 likes this.

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May 22, 2009, 13:40		#4
LKF New Member Join Date: Mar 2009 Posts: 16 Rep Power: 17	I think this link offers a fairly good explanation of the difference between the two averaging methods. http://www.cfd-online.com/Forums/cfx...a-average.html