  The current study focuses on experimentally and theoretically improving the
characterization of the drop size and drop velocity for like-on-like doublet
impinging jets. The experimental measurements were made using phase Doppler
anemometry (PDA) at jet Weber numbers We j corresponding to the impact wave
regime of impinging jet atomization. A more suitable dynamic range was used for
PDA measurements compared to the literature, resulting in more accurate
experimental measurements for drop diameters and velocities. There is some
disagreement in the literature regarding the ability of linear stability
analysis to accurately predict drop diameters in the impact wave regime. This
work seeks to provide some clarity. It was discovered that the assumed uniform
jet velocity profile was a contributing factor for deviation between diameter
predictions based on models in the literature and experimental measurements.
Analytical expressions that depend on parameters based on the assumed jet
velocity profile are presented in this work. Predictions based on the parabolic
and 1/7th power law turbulent profiles were considered and show better
agreement with the experimental measurements compared to predictions based on
the previous models. Experimental mean drop velocity measurements were compared
with predictions from a force balance analysis, and it was observed that the
assumed jet velocity profile also influences the predicted velocities, with the
turbulent profile agreeing best with the experimental mean velocity. It is
concluded that the assumed jet velocity profile has a predominant effect on
drop diameter and velocity predictions.
