Contributed by the Tribology Division for publication in the ASME JOURNAL OF TRIBOLOGY. Manuscript received by the Tribology Division August 29, 2001 revised manuscript received December 27, 2001. Associate Editor: M. M. Khonssari.
When two circular discs are supplied with air under pressure through a central hole, the lower disc will be attracted or repelled. Willis 1 in 1828 first described an experiment to study radial flow between a pair of parallel discs with air supplied through a tube to the center of one of the discs. He found that, for a constant air supply, as the two discs were brought together the force between the discs was initially repulsive then became attractive and eventually repulsive and of a much greater magnitude when very close together. Theoretical solutions have been discussed in references 2,3,4,5,6,7,8,9,...
