Light scattering patterns of pendant drops. I. Experimental investigation

Measurement of material properties (surface tension, evaporation rate,…) is essential to many processes, such as fluid mechanics, combustion science, engineering chemistry, and petroleum science. pendant drop imaging is one of the most popular methods. The light scattering technique is also used because of its rapidity and precision, but it is limited to spherical drops due to the lack of theoretical tools to predict the scattering patterns of non-spherical objects. In the two joint papers we provide an in-depth investigation of the scattering patterns of pendant drops from two aspects: experimental observation and numerical simulation thanks to our vectorial complex ray model (VCRM) aiming to lay the foundation for the development of light scattering measurement techniques. The current paper focuses on the experimental realization to obtain high-quality scattering patterns, their qualitative investigation of the relation of the scattering patterns with the morphology (size and shape) of the drops, and the measurement of the radius of a pendant drop by scattering diagram in the equatorial plane. The last point is a good example to show the feasibility and advantages of the scattering method. The measurement technique based on three-dimensional light scattering patterns to obtain the properties of pendant drops remains to be developed.