How to calculate swirl velocity or angular velocity in a in-cylinder flow analysis us

tgsankar · February 23, 2016, 11:07

I am doing an in-cylinder steady state flow analysis. In that I need to calculate the angular velocity of air rotating
about the cylinder axis. I have been using a custom field function to monitor the velocity. The field function is
given as: (x*Vz-z*Vx)/(x*x+z*z). While using this field function the velocity fluctuates between a maximum and
minimum valve. It does not settle or converge even the solution is converged.

I need to know whether the field function is correct or wrong? Why the value fluctuates?

I really need this explanation which will help me in my project work.
If anybody experienced this same issue, please let me know.
Thanks in advance.

fluid23 · February 23, 2016, 13:25

Depending on what software you are using, you can probably setup a cylindrical coordinate system and then treat it just like x y z components except get axial, tangential and radial flow velocities.

zkhn · April 26, 2017, 17:55

You have to calculate $\nabla$ $\times$ V, i.e curl of the velocity field.

February 23, 2016, 11:07	How to calculate swirl velocity or angular velocity in a in-cylinder flow analysis us	#1
tgsankar New Member Gomathi shankar Join Date: Mar 2014 Posts: 2 Rep Power: 0	I am doing an in-cylinder steady state flow analysis. In that I need to calculate the angular velocity of air rotating about the cylinder axis. I have been using a custom field function to monitor the velocity. The field function is given as: (xVz-zVx)/(xx+zz). While using this field function the velocity fluctuates between a maximum and minimum valve. It does not settle or converge even the solution is converged. I need to know whether the field function is correct or wrong? Why the value fluctuates? I really need this explanation which will help me in my project work. If anybody experienced this same issue, please let me know. Thanks in advance.

April 26, 2017, 17:55	Curl of the velocity field	#3
zkhn New Member Muhammad Zahid Join Date: Aug 2015 Posts: 2 Rep Power: 0	You have to calculate $\nabla$ $\times$ V, i.e curl of the velocity field.

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February 23, 2016, 13:25		#2
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 18	Depending on what software you are using, you can probably setup a cylindrical coordinate system and then treat it just like x y z components except get axial, tangential and radial flow velocities.