The Diffusion Fish

ORAL

Abstract

Nature has evolved a prodigious variety of propulsion mechanisms. We have discovered a remarkable new one that requires no moving parts, instead coupling molecular diffusion and gravity to spontaneously propel asymmetric objects in stratified fluids. This can occur in lakes or marine environments, where temperature and salinity often create stable density gradients. The phenomenon is demonstrated using a triangular wedge, ``the diffusion fish,'' in salt-stratified water.

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Authors

  • Tom Peacock

    MIT - Mechanical Engineering, Massachusetts Institute of Technology, MIT

  • Roman Stocker

    MIT - Civil and Environmental Engineering, MIT

  • Eric Lauga

    University of California, San Diego, MIT, UCSD, UC, San Diego

  • Chiang Mei

    Massachusetts Institute of Technology, MIT