74th Annual Meeting of the APS Division of Fluid Dynamics (November 21, 2021 — November 23, 2021)

V0036: Chemical Flowers: buoyancy-driven instabilities under modulated gravity

Authors
  • Yorgos Stergiou, Helmholtz-Zentrum Dresden-Rossendorf
  • Dezso Horvath, University of Szeged
  • Gabor Schuszter, University of Szeged
  • Marcus Hauser, Otto-von-Guericke-Universität Magdeburg
  • Anne De Wit, Université libre de Bruxelles
  • Kerstin Eckert, Helmholtz-Zentrum Dresden-Rossendorf
  • Karin Schwarzenberger, Helmholtz-Zentrum Dresden-Rossendorf
DOI: https://doi.org/10.1103/APS.DFD.2021.GFM.V0036

In this video, we present experiments of a miscible reactive horizontal displacement in a radial Hele-Shaw cell under modulating gravity levels.

Initially, the Hele-Shaw cells are filled with a colorless solution of KSCN, and the injected fluid is a colorless solution of FeNO3. When the two solutions react, a complex ion (FeSCN2+) forms resulting in a red-colored product solution. Due to the direct visualization of the formed product using a white LED light array and a monochrome camera, this chemical system is convenient to study reaction-diffusion-convection fronts [1].

The gravity modulations were achieved aboard the 73rd ESA Parabolic Flight Campaign that took place in October, 2020 in Paderborn, Germany. The parabolic flight allowed for experiments under micro-g, normal-g and hyper-g conditions and the transition between them.

These experiments provided detailed insights in a previously investigated [2] buoyancy-driven instability. In particular, the effect of hyper-g and multiaxial acceleration on the pattern formation was revealed. The observation of the system under micro-g confirmed that no instability develops in the absence of buoyancy effects.

[1] A. Tóth, G. Schuszter, N.P. Das, E. Lantos, D. Horváth, A. De Wit, F. Brau, Effects of radial injection and solution thickness on the dynamics of confined A+ B→ C chemical fronts. Phys Chem Chem Phys, 22(18), 2020

[2] F. Haudin, L. A. Riolfo, B. Knaepen, G. M. Homsy, A. De Wit. Experimental study of a buoyancy-driven instability of a miscible horizontal displacement in a Hele-Shaw cell. Phys. Fluids, 26(4), 2014

Music: The Placing Rule by Small Colin
Promoted by: ctrax.com/small-colin/entry/the-placing-rule
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