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Seminário Águas Abertas - IPH - Prof. Guillermo Artana (28/06/2018 às 15:00)

Prezados colegas,

É com grande prazer que convidamos à comunidade do IPH (professores, pesquisadores, graduandos, pós graduandos, técnicos,etc.) para mais uma edição do encontro Águas Abertas IPH:

“Some aspects of flows in soap films: a quasi 2D flow benchmark”


Prof. Dr. Guillermo ARTANA (UBA, Argentina).

O Dr. G. Artana é professor da Universidade de Buenos Aires, atuando no Laboratório de Fluido Dinâmica da Facultad de Ingeniería, e é pesquisador do CONICET. A palestra abordará a análise teórico-experimental de escoamentos de filmes de sabão, nos quais as forças de tensão superficial jogam um rol fundamental.


O evento ocorrerá no dia 28/06/2018 (quinta-feira) das 15:00 às 16:00 no Auditório Prof. Marc Pierre Bordas do IPH.

Soap film flows involve complex phenomena in which surface tension forces play an important role. A 2D (or
quasi 2D) analog of the observed flow dynamics can however be found in configurations where no interfacial
forces exist. In this talk we address three problems that are of interest when analyzing this kind of flows.
The first one concerns establishing to which extent the results obtained with soap film flows can give useful
information of a more general 2D fluid flow (or quasi 2D flow). This kind of problem has been previously
considered by J.M. Chomaz
1. This author found that the experimental conditions under which both dynamics
can be linked are quite restrictive: we revisit these results establishing less restrictive conditions
The second one is related to developments of experimental techniques that can be used with these flows for
velocimetry purposes. Soap film flows are known to produce remarkable flow visualizations but quantitative
analysis extracted from the images has not been fully explored. We present and discuss results using two
different techniques of visualization (interferometry and Schlieren) whose images are post processed with
classical correlation techniques (Particle Image Velocimetry) or with a dense motion estimator.
Finally, we consider the eulerian time spectrum of 2D turbulent soap film flows focusing our study on the
characteristics of the associated spatial structures. The development of energy cascade concepts requires a
schematic “eddy” with a single wave number associated, however distinctions between real eddies and waves
3. We perform an analysis with the Chronos-Koopman spectral technique4 that enables to circumvent
some of the limitations of the classical Fourier analysis. The use of this approach produces power spectra with
slopes compatible with the enstrophy and energy cascades, giving access to the associated spatial modes that
show definite wavenumber structures. We analyze possible coupling of these structures and conclude about
the validity of Taylor hypothesis and on intermittency of the turbulence in this flow.