Heat transfer from artificial hailstones

The rate of melting of realistically rough artificial hailstones in an airstream has been measured and the dependence of the rate of heat transfer on Reynolds number determined. The rates of heat transfer show a marked divergence from the values for smooth spheres as the Reynolds number increases from 104 to 2 × 105. The results indicate that the effective critical liquid water concentrations of large hailstones (diameters greater than 6 cm) are 1·2 to 3 times those previously computed.