PERFORATED DISC 



WATER SURFACE 

 INNER CYLINDER 

 OUTER CYLINDER 



BAFFLE 

 OUTLET 



Fig. 2 - Apparatus for creating 

 a draining vortex 



(a) Draining vortex 



(b) The interference of a 

 thin rod with the vortex 



Fig. 3 - Draining vortex experiment 



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