ljssslong
Bbp_participant

Oh, I get it.  I misunderstood what color and vectors represent.  The vectors are colored by velocity magnitude of x, y and z components while in the plane, it only shows the x and y components whose resultant vectors represent the size of vectors in my graphics. No wonder the size of vectors is small away from the wall. 

Highly appreciated for your patiently explanations!!!

Best regards.

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