How to calculate velocity at a interior surface?

wanghaojie · March 23, 2012, 11:32

Im trying to get the velocity at a certain surface by udf.
First I try to use
F_U(f,t)
but when it runs, the fluent will stop and say there is an error. I further examined it and found out it can only be used for boundary surface
Then i try to calculate the surface velocity by averaging the cells before and after the surface. Then i can get results but it is different from the contour result. I think the contour results is calculated by staggered grid? So how can i get exactly the same results as in the contour by udf?

Thanks

banty · March 23, 2012, 14:21

Hi,
During contour plot we have two option like node value ( averaged value. which averaging method is unknown to user) and cell value. U can export the cell value data out of fluent and modify data as u want.

March 23, 2012, 11:32	How to calculate velocity at a interior surface?	#1
wanghaojie Member HJ Join Date: Nov 2011 Posts: 30 Rep Power: 15	Im trying to get the velocity at a certain surface by udf. First I try to use F_U(f,t) but when it runs, the fluent will stop and say there is an error. I further examined it and found out it can only be used for boundary surface Then i try to calculate the surface velocity by averaging the cells before and after the surface. Then i can get results but it is different from the contour result. I think the contour results is calculated by staggered grid? So how can i get exactly the same results as in the contour by udf? Thanks

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March 23, 2012, 14:21		#2
banty Member banty Join Date: Mar 2012 Posts: 52 Rep Power: 14	Hi, During contour plot we have two option like node value ( averaged value. which averaging method is unknown to user) and cell value. U can export the cell value data out of fluent and modify data as u want.