Greetings-

  I'm trying to find information on the effects of a particle's size
during flow in a microchannel in a Particle Image Velocimetry (PIV)
experiment.
  I'd like to know the relation between channel dimensions and
apporpriate particle size for PIV.  Regarding the subject, I've read
Nguyen and Wereley's book as well as some papers by Meinhart and
Santiago which talk about effects due to Brownian motion an Stokes drag.
 But I haven't found an explanation or equation directly relating
particle size and channel dimensions.

  Also, thanks for the responses I got to my previous PIV posting.  In
the end I didn't use a special particle tracking software: I simply
measured particle displacement between frames using IrfanView which was
adaquate for my application.

Michael