ABSTRACT
I. INTRODUCTION Electrohydrodynamics is often carried out by persons trained in either electrostatics or fluid mechanics, but rarely both. As a result, it is often difficult to foresee how the electrical and mechanical effects will interact in the laboratory. One useful approach to this problem is the comparison of the various forces that arise naturally in electrohydrodynamics. By sorting and comparing these quantities, it is usually possible to predict the overall results of an experiment by using “back of the envelope” calculations. In many cases, the systematic study of dimensionless ratios can also expose the possibility of new interactions not considered in the initial planning.
