I am sorry.
My English is poor.
I have received the help of translation Google.

Two models, the conditions are the same for all. (Dimensions, mesh ...)

but, I changed only impeller.

However, a problem occurs in the pressure.

Power problems, customs, until the pressure for efficiency.

The same phenomenon occurs even when viewed from the beginning.

All of the same phenomenon occurs SW2012 Sp5.0 & SW2013 Sp2.0.

What is the problem?

Is it a bug in the SolidWorks program?

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Not in the direction of the wind through the Local Mesh Part?