Water Volume Present in Domain

RAJDEEP · November 14, 2019, 23:37

Hello everyone,

i am carrying out multiphase simulation in rotating domain in cfx. I want to know about, how can i monitor the water volume which is present within the entire domain as one of my boundary condition is opening?

From my understanding, expression would be,

volume (Water.Volume Fraction==1)@Default Domain

The above expression is providing me an error.

Please help me out to solve it.

Regards,
RAJDEEP JAGDALE

Gert-Jan · November 15, 2019, 02:56

try volumeInt(Water.Volume Fraction)@Default Domain

RAJDEEP · November 15, 2019, 03:28

Thanks for the information and the expression you told worked perfectly well.

My related query is, can't i use the conditional expression like "Water.Volume Fraction ==1" as mentioned earlier.

Gert-Jan · November 15, 2019, 03:50

Why would you want this? Do you want to neglect all elements where air is present? Even with only 1% air and 99% water?

Gert-Jan · November 15, 2019, 03:59

You can do something like this:

volumeInt(step(Water.Volume fraction - 0.5)*Water.Volume fraction))@Default Domain

The term step(Water.Volume fraction - 0.5) will be zero where the volume fraction is lower than 0.5 and 1 if it is higher than 0.5. In this way CFX will not include the elements with Water.volume fractions lower than 0.5.

You can change 0.5 into 0.9999, ignoring the elements with more than 1e-4 air. Then I'm not sure if something will be left to integrate ;-)

November 14, 2019, 23:37	Water Volume Present in Domain	#1
RAJDEEP New Member RAJDEEP JAGDALE Join Date: Oct 2018 Posts: 26 Rep Power: 7	Hello everyone, i am carrying out multiphase simulation in rotating domain in cfx. I want to know about, how can i monitor the water volume which is present within the entire domain as one of my boundary condition is opening? From my understanding, expression would be, volume (Water.Volume Fraction==1)@Default Domain The above expression is providing me an error. Please help me out to solve it. Regards, RAJDEEP JAGDALE

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November 15, 2019, 02:56		#2
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,888 Rep Power: 27	try volumeInt(Water.Volume Fraction)@Default Domain

November 15, 2019, 03:28		#3
RAJDEEP New Member RAJDEEP JAGDALE Join Date: Oct 2018 Posts: 26 Rep Power: 7	Thanks for the information and the expression you told worked perfectly well. My related query is, can't i use the conditional expression like "Water.Volume Fraction ==1" as mentioned earlier.

November 15, 2019, 03:50		#4
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,888 Rep Power: 27	Why would you want this? Do you want to neglect all elements where air is present? Even with only 1% air and 99% water?

November 15, 2019, 03:59		#5
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,888 Rep Power: 27	You can do something like this: volumeInt(step(Water.Volume fraction - 0.5)*Water.Volume fraction))@Default Domain The term step(Water.Volume fraction - 0.5) will be zero where the volume fraction is lower than 0.5 and 1 if it is higher than 0.5. In this way CFX will not include the elements with Water.volume fractions lower than 0.5. You can change 0.5 into 0.9999, ignoring the elements with more than 1e-4 air. Then I'm not sure if something will be left to integrate ;-)