Extracting the different Two Phase forces

challenger85 · February 2, 2010, 09:41

Hi All

I have a question related to my simulations carried out. In the moment, two phase simulations are carried out using the euler euler two phase approach for monodispersed air water bubbly flow.

Since the flow is quite complicated, it would be very interesting to study the effect of the different fores which act between the two velocity fields (of the continuous and dispersed phase).

Now, as far as known, it is possible to see the forces acting for both phases (modeled fluids). It would be very helpful to extract the distinct force therms as they were calculated from the code (so for example the drag force, the lift force, the turbulent dispersion force) to judge the result and the influence of the forces one by one.

Is there a possibility to do so? Unfortunately, I did not figure this out yet.

Best Regards
Torsten Betschart

ghorrocks · February 2, 2010, 18:12

Have you looked in the CEL documentation in the reference guide? V12 has access to a lot more variables for this sort of stuff than previous versions.

I think you will have to create additional variables defined using some CEL expressions matching the equations defining these terms. I don't know of any way of extracting these variables directly - but have a look yourself, it may be there.

challenger85 · February 3, 2010, 03:30

Hello Glenn

Thanks a lot for your reply.
I looked up in the CEL documentation but could not find the quantities I was looking for. Actually, the programming of this parameters using expressions and variables is the thing I am doing in the moment; one problem is, that not all of the used constants and quantities, which show up in the equations, are eplained very well... But at least, it is possible to calculate the most important terms caused by the different gradient. I will take care of the constants in a different way.

Yes, this leads me to the next question; I checked the documentation but could not find an answer yet: do someone know if it is possible to calculate the vector product by a certain defined operator?

Best regards
Torsten

ghorrocks · February 3, 2010, 05:00

There are a number of new and undocumented CEL expression which may be of use to you. Talk to CFX support about what is available. I don't use them very much so cannot say but I remember seeing a presentation showing they are there.

February 2, 2010, 09:41	Extracting the different Two Phase forces	#1
challenger85 New Member Torsten Thomas Betschart Join Date: Nov 2009 Posts: 10 Rep Power: 17	Hi All I have a question related to my simulations carried out. In the moment, two phase simulations are carried out using the euler euler two phase approach for monodispersed air water bubbly flow. Since the flow is quite complicated, it would be very interesting to study the effect of the different fores which act between the two velocity fields (of the continuous and dispersed phase). Now, as far as known, it is possible to see the forces acting for both phases (modeled fluids). It would be very helpful to extract the distinct force therms as they were calculated from the code (so for example the drag force, the lift force, the turbulent dispersion force) to judge the result and the influence of the forces one by one. Is there a possibility to do so? Unfortunately, I did not figure this out yet. Best Regards Torsten Betschart

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February 2, 2010, 18:12		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Have you looked in the CEL documentation in the reference guide? V12 has access to a lot more variables for this sort of stuff than previous versions. I think you will have to create additional variables defined using some CEL expressions matching the equations defining these terms. I don't know of any way of extracting these variables directly - but have a look yourself, it may be there.

February 3, 2010, 03:30		#3
challenger85 New Member Torsten Thomas Betschart Join Date: Nov 2009 Posts: 10 Rep Power: 17	Hello Glenn Thanks a lot for your reply. I looked up in the CEL documentation but could not find the quantities I was looking for. Actually, the programming of this parameters using expressions and variables is the thing I am doing in the moment; one problem is, that not all of the used constants and quantities, which show up in the equations, are eplained very well... But at least, it is possible to calculate the most important terms caused by the different gradient. I will take care of the constants in a different way. Yes, this leads me to the next question; I checked the documentation but could not find an answer yet: do someone know if it is possible to calculate the vector product by a certain defined operator? Best regards Torsten

February 3, 2010, 05:00		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	There are a number of new and undocumented CEL expression which may be of use to you. Talk to CFX support about what is available. I don't use them very much so cannot say but I remember seeing a presentation showing they are there.