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Hydrodynamic drag reduction based on drop impact images

Grant number: 05/00873-8
Support type:Regular Research Grants
Duration: January 01, 2006 - March 31, 2008
Field of knowledge:Physical Sciences and Mathematics - Chemistry
Principal Investigator:Edvaldo Sabadini
Grantee:Edvaldo Sabadini
Home Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil


The presence of very small amounts (ppm) of high-MW polymers in a solution produces high levels of drag reduction in a turbulent flow. This phenomenon, often termed as the Toms Effect, is highly dependent not only on MW, but also on the flexibility of the macromolecular chain. Several experimental techniques are usually used to quantify the levels of drag reduction, and to correlate with the molecular models. However , both, the experimental results and the theoretic models are still limited. Recently we have proposed a new experimental approach of the phenomenon, based on the evolution of the structures after a collision of a drop against a shallow liquid surface, both containing a drag reducing agent. In milliseconds after the drop impact, a crown and a cavity is impinged in the liquid surface, and the collapse of these structures produces a jet named as Rayleigh jet. We have demonstrated that the jet is highly sensitive to the elongational effects due to the presence of the polymer in the solution. The stretching-contraction dynamic of the polymer chain absorbs the dissipate energies of the small vortices created in within the flow, resulting in the drag reduction. The macroscopic effect can be visualised in the high amplitude of the Rayleigh jet. The main contribution of this new technique is the correlation between the rates of the fluid deformation and the macromolecular motion.In this project we intent to study this phenomenon with more details using a very fast CCD camera. The dynamic of the liquid deformation captured from the evolution of the splash will allow us to correlate different drag reducing agents (flexible and rigid particles) with the Elastic Theory to drag reduction. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
RODRIGUES, ROBERTA K.; FOLSTA, MAURICIO G.; MARTINS, ANDRE L.; SABADINI, EDVALDO. Tailoring of wormlike micelles as hydrodynamic drag reducers for gravel-pack in oil field operations. JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING, v. 146, p. 142-148, OCT 2016. Web of Science Citations: 4.

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Filed patent(s) as a result of this research project

REDUTORES DE ATRITO HIDRODINÂMICO PARA BIOCOMBUSTÍVEIS PI0900355-0 - Universidade Estadual de Campinas (UNICAMP) . Edvaldo Sabadini; Kelly Roberta Francisco Muruci de Paula - January 2009, 21