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Emmanuel December 14, 2006 01:01

Average Facet, Surface Vertex or Area-Weighted
I want to obtain the value average velocity of the outlet of my model. I normally use REPORT=>SURFACE INTEGRAL then select AREA-WEIGHTED AVERAGE under REPORT TYPE and VELOCITY under FEILD VARIABLE.

My problem is the the value I obtain is not close to the actual experimental values. It is substansially lower than the experimental values. But, if I use FACET AVERAGE of VERTEX AVERAGE instead of AREA-WEIGHTED AVERAGE, I better values, although higher than the experimental values.

Example: In one case:

Experimental value = 95.0 m/s

Area-weighted = 64.5 m/s

Facet average = 109.8 m/s

Vertex average = 110.4 m/s

Which should I use?

hugo December 14, 2006 10:40

Re: Average Facet, Surface Vertex or Area-Weighted

If you want to report the average velocity of the oulet the correct way is use AREA-WEIGHTED AVERAGE because the velocity integral is with the Area-Weightes of each cell and the result is independent of the cell area distribution.

In the other case the result depend on the mesh because the integral is without the Area-Weighted of each cell. For example the Vertex average is the sum of all vertex values on the oulet divided by the total number of vertex.

Only in the case that you have a mesh perfectly uniform in area both case will be similar.

good luck

Musa February 4, 2012 23:04

In my case I am simulating a gas-solid fluidized bed and i would like to obtain an axial profile of the solid volume fraction. which surface monitors are best suited, line/rake or points. Secondly which report type is most suitable, facet average ,area weighted average or vertex average

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