Propulsion generated by diffusion-driven flow

Buoyancy-driven flow, which is flow driven by spatial variations in fluid density, lies at the heart of a variety of physical processes, including mineral transport in rocks, the melting of icebergs and the migration of tectonic plates. Here we show that buoyancy-driven flows can also generate propu...

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Bibliographic Details
Published in:Nature physics 2010-07, Vol.6 (7), p.516-519
Main Authors: Peacock, Thomas, Allshouse, Michael R, Barad, Michael F
Format: Article
Language:English
Subjects:
Atomic
Boundaries
Buoyancy
Classical and Continuum Physics
Complex Systems
Computational fluid dynamics
Computer simulation
Condensed Matter Physics
Density
Diffusion
Floats
Flow
Fluid dynamics
Fluid flow
Fluids
Geophysics
Icebergs
letter
Mathematical and Computational Physics
Melting
Molecular
Optical and Plasma Physics
Physics
Physics and Astronomy
Propulsion
Rocks
Theoretical
Thrust
Transport processes
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Summary:Buoyancy-driven flow, which is flow driven by spatial variations in fluid density, lies at the heart of a variety of physical processes, including mineral transport in rocks, the melting of icebergs and the migration of tectonic plates. Here we show that buoyancy-driven flows can also generate propulsion. Specifically, we find that when a neutrally buoyant wedge-shaped object floats in a density-stratified fluid, the diffusion-driven flow at its sloping boundaries generated by molecular diffusion produces a macroscopic sideways thrust. Computer simulations reveal that thrust results from diffusion-driven flow creating a region of low pressure at the front, relative to the rear of an object. This discovery has implications for transport processes in regions of varying fluid density, such as marine snow aggregation at ocean pycnoclines, and wherever there is a temperature difference between immersed objects and the surrounding fluid, such as particles in volcanic clouds.
ISSN:1745-2473
1745-2481
DOI:10.1038/nphys1686