Volume fraction in CFX

Wendy1984 · April 14, 2011, 18:03

Hi Everyone,

I'm looking at free surface flow tutorial in CFX and it sets the Water Volume Fraction to 0.5 for Isosurface in CFD-Post to show the free surface. Just wondering why it is 0.5 not 1. I tried from 0.1 to 0.9 and they give quite different values, what do they stead for?

I'm new to CFX and thank for any advices.

ghorrocks · April 15, 2011, 07:02

A water.volume fraction of 0 represents pure air and 1 represents pure water. So a value of 0.5 is just the half way point and is defined as the interface.

vishal.indomitable · September 2, 2011, 04:54

Volume of Fluid means "The volume of the fluid which you are specifying upon the volume of all the fluids which you have taken."
Ex- if you take water and air and specify vol of water as 0.2,
it means
the volume of water/ (vol of water + vol of air) = 0.2

April 14, 2011, 18:03	Volume fraction in CFX	#1
Wendy1984 New Member Wendy Join Date: Mar 2011 Posts: 4 Rep Power: 15	Hi Everyone, I'm looking at free surface flow tutorial in CFX and it sets the Water Volume Fraction to 0.5 for Isosurface in CFD-Post to show the free surface. Just wondering why it is 0.5 not 1. I tried from 0.1 to 0.9 and they give quite different values, what do they stead for? I'm new to CFX and thank for any advices. Last edited by Wendy1984; April 14, 2011 at 23:15.

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April 15, 2011, 07:02		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,693 Rep Power: 143	A water.volume fraction of 0 represents pure air and 1 represents pure water. So a value of 0.5 is just the half way point and is defined as the interface.

September 2, 2011, 04:54		#3
vishal.indomitable New Member Vishal Join Date: Feb 2011 Location: Bhopal, M.P. (India) Posts: 18 Rep Power: 15	Volume of Fluid means "The volume of the fluid which you are specifying upon the volume of all the fluids which you have taken." Ex- if you take water and air and specify vol of water as 0.2, it means the volume of water/ (vol of water + vol of air) = 0.2