Watson’s theory provides region specific expressions for the layer thickness based on the radial location for laminar and turbulent flows. The initial thickness of the sheet is given by the layer thickness at the edge of the deflector. The deflector diameter is thus an important parameter govern- ing the atomization process. Typically, only Region I and Region II have to be considered in sprinkler flow configurations. However, the film has persisted beyond Region II in a few of the cases studied.
Assuming the motion in the layer is turbulent, for a deflector diameter corresponding to a radial location within Region II where rdorl (as shown in Fig. 2), the sheet thickness is given by