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Lock-exchange experiments with an autocatalytic reaction front
I Bou Malham1, N Jarrige, J Martin
1University Pierre et Marie Curie, University Paris-Sud, CNRS. Lab FAST, Bat. 502, Campus Universitaire, Orsay, F-91405, France.
The Journal of Chemical Physics
|January 5, 2011
Summary
This study examines how buoyancy affects chemical reaction fronts in fluid dynamics, finding that front velocity and shape are linked and scale with diffusion. This research explores autocatalytic reaction fronts in lock-exchange configurations.
Area of Science:
- Fluid Dynamics
- Chemical Kinetics
- Reaction-Diffusion Systems
Background:
- Viscous lock-exchange gravity currents involve fluid exchange in channels, with fronts spreading over time.
- Autocatalytic reaction fronts can propagate as solitary waves, balancing diffusion and reaction.
- Density differences behind reaction fronts can create lock-exchange configurations.
Purpose of the Study:
- To experimentally analyze buoyancy effects on iodate arsenous acid autocatalytic reaction fronts.
- To investigate how aspect ratio and geometry (rectangular channels, cylindrical tubes) influence front behavior.
- To determine the relationship between front velocity, shape, and diffusion in a lock-exchange scenario.
Main Methods:
- Experimental analysis of autocatalytic reaction fronts in various geometries.
- Systematic variation of aspect ratios in rectangular channels and use of cylindrical tubes.
- Comparison of experimental data with lattice Bathnagar-Gross-Krook (BGK) simulations and prior studies.
Main Results:
- Observed stationary-shaped fronts spanning the cell height and propagating axially.
- Demonstrated a link between front velocity and extension.
- Showed that variations in velocity and extension scale with a single variable related to diffusion.
Conclusions:
- Buoyancy significantly influences autocatalytic reaction front dynamics in lock-exchange systems.
- Front velocity and spatial extent are coupled and predictable by a diffusion-based scaling parameter.
- The findings are consistent across different geometries and chemical systems, validating the proposed scaling.
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