Boundary Condition for Fluid-Fluid ZOnes

charles4allme · September 5, 2018, 08:26

Hey,

I want to ask of there is any boundary condition for fluid_to_fluid zones using chtMultiRegionFoam.

charles4allme · September 5, 2018, 09:28

HI, I mean boundary condition for velocity

simrego · September 5, 2018, 09:59

Hi!

Why do you have two fluid zones near each other?

charles4allme · September 5, 2018, 10:54

Quote:

Originally Posted by simrego

Hi!

Why do you have two fluid zones near each other?

Well am trying to simulate a flow through a TJunction ventilation duct, So I have divided the duct into three regions. I am doing this because I want to measure the pressure drop in each duct. I have attached the image of the ventilation duct.

simrego · September 5, 2018, 16:43

Oh okay, but in this case you don't need a conjugate heat transfer solver. And you don't have to divide the domain. Just solve as it is. And then you can calculate the pressure at some cross sections and from that you can get the pressure drop between the cross sections.

For the pressure at a given cross section you can use functionObjects or simply create a slice in paraview where you want and calculate the average pressure on that slice, etc...

charles4allme · September 6, 2018, 05:50

Thanks. The problem I encountered is that, I don't know how to define the cross sections in OpenFOAM. I thought about using topoSet and getting the CellZones but I don't think you can use cellZones. Any suggestion on how I can specify a cross section.

Thanks

simrego · September 6, 2018, 07:46

You can do it with faceZones like this:
https://cpp.openfoam.org/v6/classFoa...e.html#details

You can define the faceZones with topoSet for example.

charles4allme · September 6, 2018, 09:36

I appreciate the help. Thanks a lot.

simrego · September 6, 2018, 10:00

You are welcome!
But I think it's easier to create a slice in paraview, and integrate the pressure on that slice and divide it with the area (If you use the integrate filter it will also calculate the area for you) of the slice and you will get the average pressure.
In some cases I think it is much faster and easier than figure out how are these functionObjects works and if they are do what you want or not...
But of course it is not efficient if you have a lot of cases to compare.

September 5, 2018, 08:26	Boundary Condition for Fluid-Fluid ZOnes	#1
charles4allme Member Join Date: Feb 2018 Posts: 91 Rep Power: 8	Hey, I want to ask of there is any boundary condition for fluid_to_fluid zones using chtMultiRegionFoam.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Radiation in semi-transparent media with surface-to-surface model?	mpeppels	CFX	11	August 22, 2019 07:30
Difficulty in calculating angular velocity of Savonius turbine simulation	alfaruk	CFX	14	March 17, 2017 06:08
Wrong flow in ratating domain problem	Sanyo	CFX	17	August 15, 2015 06:20
Low torque values on Screw Turbine	Shaun Waters	CFX	34	July 23, 2015 08:16
Waterwheel shaped turbine inside a pipe simulation problem	mshahed91	CFX	3	January 10, 2015 11:19

September 5, 2018, 09:28		#2
charles4allme Member Join Date: Feb 2018 Posts: 91 Rep Power: 8	HI, I mean boundary condition for velocity

September 5, 2018, 09:59		#3
simrego Senior Member anonymous Join Date: Jan 2016 Posts: 416 Rep Power: 14	Hi! Why do you have two fluid zones near each other?

September 5, 2018, 16:43		#5
simrego Senior Member anonymous Join Date: Jan 2016 Posts: 416 Rep Power: 14	Oh okay, but in this case you don't need a conjugate heat transfer solver. And you don't have to divide the domain. Just solve as it is. And then you can calculate the pressure at some cross sections and from that you can get the pressure drop between the cross sections. For the pressure at a given cross section you can use functionObjects or simply create a slice in paraview where you want and calculate the average pressure on that slice, etc...

September 6, 2018, 05:50		#6
charles4allme Member Join Date: Feb 2018 Posts: 91 Rep Power: 8	Thanks. The problem I encountered is that, I don't know how to define the cross sections in OpenFOAM. I thought about using topoSet and getting the CellZones but I don't think you can use cellZones. Any suggestion on how I can specify a cross section. Thanks

September 6, 2018, 07:46		#7
simrego Senior Member anonymous Join Date: Jan 2016 Posts: 416 Rep Power: 14	You can do it with faceZones like this: https://cpp.openfoam.org/v6/classFoa...e.html#details You can define the faceZones with topoSet for example.

September 6, 2018, 09:36		#8
charles4allme Member Join Date: Feb 2018 Posts: 91 Rep Power: 8	I appreciate the help. Thanks a lot.

September 6, 2018, 10:00		#9
simrego Senior Member anonymous Join Date: Jan 2016 Posts: 416 Rep Power: 14	You are welcome! But I think it's easier to create a slice in paraview, and integrate the pressure on that slice and divide it with the area (If you use the integrate filter it will also calculate the area for you) of the slice and you will get the average pressure. In some cases I think it is much faster and easier than figure out how are these functionObjects works and if they are do what you want or not... But of course it is not efficient if you have a lot of cases to compare.