Expressions of cylindrical velocity

February 25, 2009, 21:21

Dear all,

I want to know the exact expressions of cylindrical velocity components in CFX. Generally speaking, velocity are calculated in cartesian coordinate system. Where I can find it? Thanks for any help...

Rikio

mic · March 17, 2009, 06:47

Rikio,
I don't know if I exactly understand your question.
Velocities are calculated in the cartesian coordinate system and are u(=vx), v(=vy) and w(=vz).
In the cylindrical coordinate system you have: radial velocity, circumferential velocity and axial velocity. If you're using the "turbo mode" you have to initialise the components and than you can calculate the velocity cylinrical components.
On the users guide the velocities components are explained.
Hope this helps.

rikio · March 17, 2009, 21:52

Thank you very much, Mic.
I am sorry for the ambiguity of the question. What I want to know is the relationship between cartesian velocity components and cylindrical velocity components, i.e. how to trasfer from cartesian components to cylindrical? Maybe it is more of mathematical, but I just want to know how it works.
Thank you again...

mic · March 18, 2009, 06:25

Hallo Rikio,
yes, it is more a mathematical issue, than a CFD one.
Have a look at:
http://en.wikipedia.org/wiki/Cylindrical_coordinates

rikio · March 18, 2009, 21:32

Thank you, mic,

You are very appreciated for kindly help. But the velocity components is more complicated than the coordinate transfer since they are vectors. However, I have derived the formulae. Thank you.

February 25, 2009, 21:21	Expressions of cylindrical velocity	#1
Rikio Guest Posts: n/a	Dear all, I want to know the exact expressions of cylindrical velocity components in CFX. Generally speaking, velocity are calculated in cartesian coordinate system. Where I can find it? Thanks for any help... Rikio

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March 17, 2009, 06:47		#2
mic New Member Join Date: Mar 2009 Location: Milan, Italy Posts: 12 Rep Power: 17	Rikio, I don't know if I exactly understand your question. Velocities are calculated in the cartesian coordinate system and are u(=vx), v(=vy) and w(=vz). In the cylindrical coordinate system you have: radial velocity, circumferential velocity and axial velocity. If you're using the "turbo mode" you have to initialise the components and than you can calculate the velocity cylinrical components. On the users guide the velocities components are explained. Hope this helps.

March 17, 2009, 21:52		#3
rikio Senior Member Rikio Join Date: Mar 2009 Location: SH, China Posts: 182 Blog Entries: 1 Rep Power: 17	Thank you very much, Mic. I am sorry for the ambiguity of the question. What I want to know is the relationship between cartesian velocity components and cylindrical velocity components, i.e. how to trasfer from cartesian components to cylindrical? Maybe it is more of mathematical, but I just want to know how it works. Thank you again...

March 18, 2009, 06:25		#4
mic New Member Join Date: Mar 2009 Location: Milan, Italy Posts: 12 Rep Power: 17	Hallo Rikio, yes, it is more a mathematical issue, than a CFD one. Have a look at: http://en.wikipedia.org/wiki/Cylindrical_coordinates

March 18, 2009, 21:32		#5
rikio Senior Member Rikio Join Date: Mar 2009 Location: SH, China Posts: 182 Blog Entries: 1 Rep Power: 17	Thank you, mic, You are very appreciated for kindly help. But the velocity components is more complicated than the coordinate transfer since they are vectors. However, I have derived the formulae. Thank you.