By using dimensional analysis, the Stokes number based on the cut diam
eter was predicted to be a function of the Reynolds number and the geo
metry of the cyclone. Data from various investigators were plotted ver
sus the Reynolds number. At lower Reynolds numbers, the Stokes number
decreased with increasing Reynolds number. At higher values of the Rey
nolds number, the data are inconclusive. For some data sets, the Stoke
s number approached a constant value, whereas, for other sets, the Sto
kes number decreased with increasing Reynolds number. The dimensionles
s data from this study can be used to estimate the cut diameter of geo
metrically similar cyclones and to make preliminary estimates for a cy
clone of a different design.