Fully Developed Flow

kpsudhakar · June 3, 2010, 07:18

Dear CFX users,
Thanks in advance,Could anyone suggest me to obtain the fully developed flow at inlet for a simple pipe cfx simulation without extending the inlet.

I tried out the following steps to achieve the fully developed flow at inlet
1)Performed a simulation specifying flow direction as normal to boundary.
2)Extract the velocity variables at outlet
3)And specify those extracted velocity variables into cartesian components as a Profile boundary at inlet.

Due to software consideration we cant assign zero velocity (Near to the wall) .So i cant achive the fully developed flow condition at inlet.

Thanks
Sudhakar

bharath · June 5, 2010, 22:51

In easy way you can do it by extending the inlet to half or use the expressions to achieve it

ghorrocks · June 6, 2010, 07:20

Why don't you save your outlet velocity as a CFX profile? Then you can impose that on the inlet as a profile and you have fully developed flow at the inlet.

kpsudhakar · June 7, 2010, 05:09

Thanks Glenn Horrocks
I tried that option ,But the profile export option neglect the near wall velocity variables(Zero Velocity).So its tough to achieve the fully developed flow at inlet.

ghorrocks · June 7, 2010, 07:03

You do not understand the CFX control volumes. The centroid of the first control volume is a distance away from the wall and hence its velocity is non-zero. The profile is correct.

June 3, 2010, 07:18	Fully Developed Flow	#1
kpsudhakar New Member Sudhakar P Join Date: Mar 2009 Location: Bangalore Posts: 10 Rep Power: 17	Dear CFX users, Thanks in advance,Could anyone suggest me to obtain the fully developed flow at inlet for a simple pipe cfx simulation without extending the inlet. I tried out the following steps to achieve the fully developed flow at inlet 1)Performed a simulation specifying flow direction as normal to boundary. 2)Extract the velocity variables at outlet 3)And specify those extracted velocity variables into cartesian components as a Profile boundary at inlet. Due to software consideration we cant assign zero velocity (Near to the wall) .So i cant achive the fully developed flow condition at inlet. Thanks Sudhakar

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June 5, 2010, 22:51		#2
bharath Senior Member Bharath kumar Join Date: Apr 2009 Posts: 169 Rep Power: 17	In easy way you can do it by extending the inlet to half or use the expressions to achieve it

June 6, 2010, 07:20		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Why don't you save your outlet velocity as a CFX profile? Then you can impose that on the inlet as a profile and you have fully developed flow at the inlet.

June 7, 2010, 05:09		#4
kpsudhakar New Member Sudhakar P Join Date: Mar 2009 Location: Bangalore Posts: 10 Rep Power: 17	Thanks Glenn Horrocks I tried that option ,But the profile export option neglect the near wall velocity variables(Zero Velocity).So its tough to achieve the fully developed flow at inlet.

June 7, 2010, 07:03		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	You do not understand the CFX control volumes. The centroid of the first control volume is a distance away from the wall and hence its velocity is non-zero. The profile is correct.