Unexpected flow angle
 

I would like to plot relative velocity angle versus span normalized at some location upstream of the leading edge.

I noticed when I use mass, length and area averaging the angles at this location change significantly.

Unexpectedly, I get different angles at shroud as follows:

length averaging: 88 deg

area averaging: 159 deg

mass averaging: 163 deg

Please note the angles at the shroud location in the attached images (span normalized: 1).

When I measure the angle using a probe in the tip it shows around 170 degrees.

Does anyone know why length averaging produce a wrong result?

Also, when I increase the number of samples the angle at the shroud keep increasing.

I mean which one of the length, area or mass averaging is more appropriate for velocity flow angle?