Measurements of the flow field in a cyclone separator with and without a re
ducing pressure drop stick (Repds) showed that the Repds reduces the peak t
angential velocity, the axial velocity gradient, and the radial gradients o
f static and total pressure and reverses the axial static pressure gradient
. These changes reduce the energy consumed by the rotating kinetic energy,
the internal friction, the turbulent kinetic energy, and the drag of the ne
gative pressure difference. The results are used to discuss why the separat
ion efficiency remains high while the pressure drop is reduced. The results
also show that a 24% "short flow" occurs near the cyclone entrance. Analys
is of the changes in the flow field and the pressure drop due to the thin s
tick shows that the Repds increases the pressure drop in the outer vortex z
one and reduces the pressure drop in the inner vortex zone. Therefore the p
ressure drop reduction with the Repds is due to its wake vortex, which lead
s to the hypothesis that the pressure drop in turbulent flow can be reduced
by adding vortexes.