Lagrangian bubble column

wafaa · November 24, 2017, 12:13

Hello!
Im trying to do a particle user fortran routine to calculate the added mass coefficient and to do so , I need to find the distance between the particles and the acceleration of each particle.

If you guys can help me with this, it would be much appreciated !
Thank you

ghorrocks · November 25, 2017, 06:36

Is this a eularian or lagrangian particle tracking model?

The distance would be calculated the same regardless of the model - you can work back from the volume fraction and particle size how many particles per unit volume and therefore their average distance apart. Important note - in lagrangian particle tracking models the tracked particles are representative of a population of particles. In other words, there are more particles than is modelled in the particle tracks.

Acceleration is a bit more tricky. I guess if this is lagrangian you can double differentiate the particle position to get the acceleration. I would need to do some thinking to determine this for Eularian models.

wafaa · November 25, 2017, 10:37

It's for a lagrangian model

ghorrocks · November 26, 2017, 18:36

OK, thanks. Do my suggestions help?

wafaa · November 29, 2017, 14:06

The thing is , my professor asked me to isolate 3 air bubbles (in air bubble column) and use the equations to calculate the added mass force that require the distance between the bubble 1 and 2 , the bubble 1 and 3 and also the acceleration of each of those bubbles. I'm not familiar with fortran user routine. If you guide me, that would be appreciated.

ghorrocks · November 29, 2017, 17:48

The CFX documentation has several examples of user fortran. There are more on the ANSYS Customer website.

November 24, 2017, 12:13	Lagrangian bubble column	#1
wafaa New Member wafaa hana Join Date: Nov 2017 Location: Montreal Posts: 4 Rep Power: 9	Hello! Im trying to do a particle user fortran routine to calculate the added mass coefficient and to do so , I need to find the distance between the particles and the acceleration of each particle. If you guys can help me with this, it would be much appreciated ! Thank you

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November 25, 2017, 06:36		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Is this a eularian or lagrangian particle tracking model? The distance would be calculated the same regardless of the model - you can work back from the volume fraction and particle size how many particles per unit volume and therefore their average distance apart. Important note - in lagrangian particle tracking models the tracked particles are representative of a population of particles. In other words, there are more particles than is modelled in the particle tracks. Acceleration is a bit more tricky. I guess if this is lagrangian you can double differentiate the particle position to get the acceleration. I would need to do some thinking to determine this for Eularian models.

November 25, 2017, 10:37		#3
wafaa New Member wafaa hana Join Date: Nov 2017 Location: Montreal Posts: 4 Rep Power: 9	It's for a lagrangian model

November 26, 2017, 18:36		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	OK, thanks. Do my suggestions help?

November 29, 2017, 14:06		#5
wafaa New Member wafaa hana Join Date: Nov 2017 Location: Montreal Posts: 4 Rep Power: 9	The thing is , my professor asked me to isolate 3 air bubbles (in air bubble column) and use the equations to calculate the added mass force that require the distance between the bubble 1 and 2 , the bubble 1 and 3 and also the acceleration of each of those bubbles. I'm not familiar with fortran user routine. If you guide me, that would be appreciated.

November 29, 2017, 17:48		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	The CFX documentation has several examples of user fortran. There are more on the ANSYS Customer website.