# UDF component in Cyliderical Velocity?

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 April 18, 2001, 04:56 UDF component in Cyliderical Velocity? #1 Hongchan Kim Guest   Posts: n/a Hi. I'm trying to use UDF for setting cylinderical velocity component in fluid zone. I knew that the swirl velocity component is "C_WSWIRL" from the manual, but I don't know the others , that is "axial velocity component" and "radial velocity component". Does anybody know this udf component? If there is no component in UDF, I have to convert these cylinderical components to x,y,z coordinate components, and this makes the code complex. - -; Thanks... Have a nice day

 April 18, 2001, 15:02 Re: UDF component in Cyliderical Velocity? #2 Amadou Sowe Guest   Posts: n/a If it is alright, can you explain what exactly you are trying to do?

 April 20, 2001, 21:52 Re: UDF component in Cyliderical Velocity? #3 Hongchan Kim Guest   Posts: n/a > If it is alright, can you explain what exactly you are trying to do? Yes, I can explain my problem. My object is to fix velocity(in Cylinderical Coordinate) in reacting vessel. I want to fix velcity components in some part of vessel, not whole. In reacting vessel system, it's easier to use cylinderical coordinate system(axial, radial, tangential) than orthogonal coordinate system(x,y,z) because of their geometry. So I want to know velocity components of cylinderical coordinate in UDF. Thanks... I

 April 24, 2001, 12:20 Re: UDF component in Cyliderical Velocity? #4 Amadou Sowe Guest   Posts: n/a Depending on how complicated your geometry is, it might not be difficult to transform x-y-z velocity components to r-theta-z components. On the other hand, if you can create structured mesh for Fluent4 you can use the FIX command that is designed to do the kinds of things you want. See Fluent 4 users guide vol. 3, chapter 14.16 for more information on the FIX command. In Fluent4 you can actually choose to work in cylindrical coordinates. This is a very nice feature for me.