Speaker
Description
It is intuitive that stirring homogenizes and increases the efficiency of liquid chemical reactions. However, in complex nonlinear systems, stirring can also alter intrinsic dynamics. Such systems may show bistability, excitability, or periodicity. A prominent example is the Belousov-Zhabotinsky reaction, where stirring effects have long been studied \cite{menzinger_concentration_1990,strizhak_stirring_1996,ruoff_excitability_1982}. In a closed ferroin-catalyzed batch reaction, high stirring rates within the periodic regime suppress oscillations \cite{ruoff_excitability_1982}. Experiments show that oscillations reappear once stirring stops or the stirring rate is decreased. For moderate stirring rates, oscillations remain, but amplitudes increase after stirring stops. The effect also depends on reaction volume, geometry, and the phase at which stirring begins.
Due to the complex interplay of reaction, diffusion, and convection, theoretical explanation is challenging \cite{noszticzius_hydrodynamic_1991,kalishyn_stirring_2010}. We aim to model the effect using diffusion-controlled reactions where the diffusion is affected by the turbulence created by the process of stirring. We conjecture that the stirring rate acts as a bifurcation parameter and present a detailed overview of our experimental findings and discuss a first version of the proposed model.
Bibliography
@article{menzinger_concentration_1990,
title = {Concentration fluctuations and stirring effects in the {Belousov}-{Zhabotinskii} reaction},
volume = {94},
issn = {0022-3654, 1541-5740},
url = {https://pubs.acs.org/doi/abs/10.1021/j100373a045},
doi = {10.1021/j100373a045},
language = {en},
number = {10},
urldate = {2026-03-15},
journal = {The Journal of Physical Chemistry},
author = {Menzinger, Michael. and Jankowski, Peter.},
month = may,
year = {1990},
pages = {4123--4126},
}
@article{strizhak_stirring_1996,
title = {Stirring {Effect} on the {Bistability} of the {Belousov}−{Zhabotinsky} {Reaction} in a {CSTR}},
volume = {100},
issn = {0022-3654, 1541-5740},
url = {https://pubs.acs.org/doi/10.1021/jp962504i},
doi = {10.1021/jp962504i},
language = {en},
number = {49},
urldate = {2026-03-15},
journal = {The Journal of Physical Chemistry},
author = {Strizhak, P. and Menzinger, M.},
month = jan,
year = {1996},
pages = {19182--19186},
}
@article{ruoff_excitability_1982,
title = {Excitability in a closed stirred {Belousov}—{Zhabotinskii} system},
volume = {90},
issn = {00092614},
url = {https://linkinghub.elsevier.com/retrieve/pii/0009261482833289},
doi = {10.1016/0009-2614(82)83328-9},
language = {en},
number = {1},
urldate = {2026-03-15},
journal = {Chemical Physics Letters},
author = {Ruoff, Peter},
month = jul,
year = {1982},
pages = {76--80},
}
@article{noszticzius_hydrodynamic_1991,
title = {Hydrodynamic turbulence and diffusion-controlled reactions: simulation of the effect of stirring on the oscillating {Belousov}-{Zhabotinskii} reaction with the {Radicalator} model},
volume = {95},
issn = {0022-3654, 1541-5740},
shorttitle = {Hydrodynamic turbulence and diffusion-controlled reactions},
url = {https://pubs.acs.org/doi/abs/10.1021/j100170a038},
doi = {10.1021/j100170a038},
language = {en},
number = {17},
urldate = {2026-03-15},
journal = {The Journal of Physical Chemistry},
author = {Noszticzius, Zoltan and Bodnar, Zsolt and Garamszegi, Laszlo and Wittmann, Maria},
month = aug,
year = {1991},
pages = {6575--6580},
}
@article{kalishyn_stirring_2010,
title = {Stirring {Effect} on the {Belousov}-{Zhabotinsky} {Oscillating} {Chemical} {Reactions} in a {Batch}. {Experimental} and {Modelling}},
volume = {65},
copyright = {http://creativecommons.org/licenses/by-nc-nd/3.0/},
issn = {1865-7109, 0932-0784},
url = {https://www.degruyter.com/document/doi/10.1515/zna-2010-1-215/html},
doi = {10.1515/zna-2010-1-215},
abstract = {We have studied the stirring effect on the time-delayed bifurcations of transient oscillations in the Belousov-Zhabotinsky (BZ) oscillating chemical reaction in a closed system. Experiments show that oscillations disappear through the time-delayed Hopf bifurcations, whose parameters depend on the stirring rate. The explanation of the stirring effect is based on the theories of diffusion-controlled reactions and hydrodynamic turbulence. We show that an increase of the stirring rate leads to an increase of the rate constant for the diffusion-controlled reaction. We propose a kinetic scheme that describes the effect observed in the experiments. A good agreement between the experimental data and the simulations is obtained.},
language = {en},
number = {1-2},
urldate = {2026-03-15},
journal = {Zeitschrift für Naturforschung A},
author = {Kalishyn, Yevhen Yu. and Rachwalska, Małgorzata and Strizhak, Peter E.},
month = jan,
year = {2010},
pages = {132--140},
}
