Terminal velocity formula for spheres in a viscous fluid

Various attempts have been made to develop a general expression for the terminal velocity of spheres in a viscous fluid (Stokes, Prandtl, Oseen, Rubey, etc.: see Bogardi, 1974 and Vanoni, 1975). All of these formulae show a lack of accuracy and/or are restrict ed to a relatively small range of Reynolds numbers. Since sieving is a time consuming...