Length of interface in VOF

IndrajitW · October 15, 2013, 05:52

Hi all,
I am simulating a two phase flow using VOF model in fluent. I need to know the length of the liquid vapor interface in the cell. This length of the interface is used in one of my UDF's.Is there any macro or something in fluent whic hcould give me acces to the interface length???

Regards,
Indrajit

bansa9643 · October 22, 2013, 13:51

Hello,
Look up Interfacial Area Density.. it will involve writing a udf which allows an estimation of the interface's "length" in each cell.
Best,
A.B.

garvitgoel · June 5, 2014, 10:59

Hi,
Can somebody please post more information on how to estimate the length of interface in the cell?
Thanks

bansa9643 · June 6, 2014, 03:36

Check Yuri Egorov's (Ansys Fluent) year 2004, work on "Validation of CFD codes with PTS - relevant test cases".
Some approximations for calculating interfacial length have been provided as a function of volume fraction and its gradient in each interfacial cell.
This approximation was found to be best suited for curved interfaces:

A = 6 * alpha_l * alpha_g * SQRT( grad(alpha_l) * grad(alpha_g) )
A = 6 * alpha_l * (1-alpha_l) * mag ( grad(alpha_l))

A being the Interfacial area density
alpha_l the liquid volume fraction
grad(alpha_l) the gradient of liquid volume fraction

A UDF could then be used to calculate the interfacial length for each cell.

Best,
A.B.

circle · April 17, 2019, 05:44

I want to read this article, can you share it with me? Thank you.

October 15, 2013, 05:52	Length of interface in VOF	#1
IndrajitW Member Indrajit Join Date: Nov 2012 Posts: 33 Rep Power: 13	Hi all, I am simulating a two phase flow using VOF model in fluent. I need to know the length of the liquid vapor interface in the cell. This length of the interface is used in one of my UDF's.Is there any macro or something in fluent whic hcould give me acces to the interface length??? Regards, Indrajit

June 5, 2014, 10:59	interface length in the cell	#3
garvitgoel New Member Garvit Goel Join Date: May 2014 Posts: 11 Rep Power: 11	Hi, Can somebody please post more information on how to estimate the length of interface in the cell? Thanks

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October 22, 2013, 13:51		#2
bansa9643 New Member A Join Date: Nov 2012 Location: France Posts: 7 Rep Power: 13	Hello, Look up Interfacial Area Density.. it will involve writing a udf which allows an estimation of the interface's "length" in each cell. Best, A.B.

June 6, 2014, 03:36		#4
bansa9643 New Member A Join Date: Nov 2012 Location: France Posts: 7 Rep Power: 13	Check Yuri Egorov's (Ansys Fluent) year 2004, work on "Validation of CFD codes with PTS - relevant test cases". Some approximations for calculating interfacial length have been provided as a function of volume fraction and its gradient in each interfacial cell. This approximation was found to be best suited for curved interfaces: A = 6 * alpha_l * alpha_g * SQRT( grad(alpha_l) * grad(alpha_g) ) A = 6 * alpha_l * (1-alpha_l) * mag ( grad(alpha_l)) A being the Interfacial area density alpha_l the liquid volume fraction grad(alpha_l) the gradient of liquid volume fraction A UDF could then be used to calculate the interfacial length for each cell. Best, A.B.

April 17, 2019, 05:44		#5
circle New Member John Join Date: Mar 2019 Posts: 2 Rep Power: 0	I want to read this article, can you share it with me? Thank you.