Affiliations: Departamento de Físico-Química,
Instituto de Química, Universidade Estadual de Campinas, Caixa Postal
154, CEP 13083-970, Campinas, São Paulo, Brazil., e-mail:
[email protected]
Abstract: The splash is a phenomenon which happens on droplet impact against a
shallow liquid surface (target), forming a structure called crown. After the
collapse of the crown, a liquid column (Rayleigh jet) arises on the surface.
Splashing has been studied from a great variety of viewpoints, in different
fields such as: agronomy, biology, engineering, astronomy, photography and
marketing. The visualization of the splash was used, in our case, to study the
drag reduction effect that happens when very low concentrations of a high
molecular weight polymer is present in the fluid under investigation. We have
developed a controlled drop-releasing device, fitted with a high-speed CCD
camera [with shutter speed of 1/10000 s], and an image acquisition and
processing system. Using this assembly, it was possible to observe large
changes in the splash structures of water, especially in the extension of the
Rayleigh jet. This result was associated with the drag reduction effect
produced by the polymer. Result obtained with the dyed drop technique has shown
that the presence of the polymer affects the mixture of the liquids from the
droplet and target.
