An exact similarity solution is given for the flow of a fluid-particle suspension over an infinitely
large disk rotating at a constant velocity. Numerical solutions of the resulting ordinary differential
equations provide velocity distributions for both fluid and solid phases and density distributions
for the solid. The boundary-layer thicknesses of the particle cloud and the fluid are found to be approximately
equal. In addition to its intrinsic value as a solution to a physical problem, the results provide a convenient basis for judging the accuracy of approximate techniques