Mass-transfer data were obtained for the vaporization of naphthalene into a turbulent gas stream flowing in an annulus. Both the inside rod and the outer pipe of the annular conduit were made of naphthalene.

To correlate the data, the investigator predicted that the mass-transfer coefficient would depend on the velocity of the flowing stream, v_∞, the diameter of the rod, D₀, the inside diameter of the outer pipe, D₀ the density and viscosity of the gas medium, and the diffusivity of naphthalene in the gas medium.

Arrange these variables into dimensionless groups that the investigators might elect to use to correlate their data.