RMS Velocity coordinates transform?

ray_lo · July 6, 2016, 23:54

Dear all,

I have the RMS fluctuating velocities in Cartesian coordinate taken from a FLUENT LES simulation. But I now need to check the the RMS fluctuating velocities in cylindrical coordinate.

Do anybody know how to transform RMS fluctuating velocities from Cartesian to cylindrical?

Many thanks

Ray

ray_lo · July 9, 2016, 05:08

figure it out. actually quite easy ~_~ .
I will put the answer here just for people who may need a quick answer of it.

radial:
ur_rms=sqrt(cos(theta)*cos(theta)*SQR(ux_rms)+sin( theta)*sin(theta)*SQR(uy_rms)+2*cos(theta)*sin(the ta)*uv)

tangential:
ut_rms=sqrt(cos(theta)*cos(theta)*SQR(uy_rms)+sin( theta)*sin(theta)*SQR(ux_rms)-2*cos(theta)*sin(theta)*uv)

July 6, 2016, 23:54	RMS Velocity coordinates transform?	#1
ray_lo New Member Ray Join Date: Oct 2015 Posts: 4 Rep Power: 10	Dear all, I have the RMS fluctuating velocities in Cartesian coordinate taken from a FLUENT LES simulation. But I now need to check the the RMS fluctuating velocities in cylindrical coordinate. Do anybody know how to transform RMS fluctuating velocities from Cartesian to cylindrical? Many thanks Ray

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[UDF] Relative coordinates in logarithmic velocity profile	cfdworker	Fluent UDF and Scheme Programming	25	July 13, 2017 03:44
RMS velocity	bageshwar	Main CFD Forum	0	October 17, 2011 04:05
velocity components in cylindrical coordinates	iperten	CFX	2	March 31, 2009 08:22
coordinates transform about RMS velocity	lcw	FLUENT	1	May 16, 2006 06:02
RMS velocity coordinates transform ???	lcw	FLUENT	0	February 22, 2006 22:29

July 9, 2016, 05:08		#2
ray_lo New Member Ray Join Date: Oct 2015 Posts: 4 Rep Power: 10	figure it out. actually quite easy ~_~ . I will put the answer here just for people who may need a quick answer of it. radial: ur_rms=sqrt(cos(theta)cos(theta)SQR(ux_rms)+sin( theta)sin(theta)SQR(uy_rms)+2cos(theta)sin(the ta)uv) tangential: ut_rms=sqrt(cos(theta)cos(theta)SQR(uy_rms)+sin( theta)sin(theta)SQR(ux_rms)-2cos(theta)sin(theta)uv)