A similarity analysis of the droplet trajectory equation

A procedure is established to reduce the number of similarity parameters in the trajectory equation for particles in a moving fluid. This is accomplished by the use of an approximate sphere drag law to derive a new trajectory scaling parameter. The modified inertia parameter proposed by Langmuir specifically for the aircraft icing problem is analyzed and for the first time a closed-form solution is obtained. Both experimental and analytical results are presented to verify this new trajectory scaling parameter.