Title :

Fluctuations and correlations of reactive scalars near chemical equilibrium in incompressible turbulence

Author(s) :

Wu, Wenwei [Auteur]
Université du Littoral Côte d'Opale [ULCO]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Calzavarini, Enrico [Auteur]
Laboratoire de Mécanique de Lille - FRE 3723 [LML]
Unité de Mécanique de Lille - ULR 7512 [UML]
Schmitt, François G [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Wang, Lipo [Auteur]

Journal title :

Physical Review Fluids

Pages :

084608

Publisher :

American Physical Society

Publication date :

2020-08-21

ISSN :

2469-990X

HAL domain(s) :

Science non linéaire [physics]

English abstract : [en]

The statistical properties of species undergoing chemical reactions in a turbulent environment are studied. We focus on the case of reversible multicomponent reactions of second and higher orders, in a condition close to ...
Show more >The statistical properties of species undergoing chemical reactions in a turbulent environment are studied. We focus on the case of reversible multicomponent reactions of second and higher orders, in a condition close to chemical equilibrium sustained by random large-scale reactant sources, while the turbulent flow is highly developed. In such a state a competition exists between the chemical reaction that tends to dump reactant concentration fluctuations and enhance their correlation intensity and the turbulent mixing that on the contrary increases fluctuations and removes relative correlations. We show that a unique control parameter, the Damköhler number (Daθ), which can be constructed from the scalar Taylor microscale, the reactant diffusivity, and the reaction rate, characterizes the functional dependence of fluctuations and correlations in a variety of conditions, i.e., at changing the reaction order, and the Reynolds and Schmidt numbers. The larger is such a Damköhler number the more depleted are the scalar fluctuations as compared to the fluctuations of a passive scalar field in the same conditions, and vice versa the more intense are the correlations. A saturation in this behavior is observed beyond Daθ≃O(10). We provide an analytical prediction for this phenomenon which is in excellent agreement with direct numerical simulation results.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Collections :

• Unité de Mécanique de Lille (UML) - ULR 7512

Source :

Harvested from HAL