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Research > Stratified Flows

We are active in researching all manner of fundamental phenomena in density-stratified fluids. One of our novel discoveries is that objects floating in a density stratification will naturally be propelled by virtue of spontaneous flows that arise on their sloping surfaces. This forcing may be even stronger if the boundaries induce flow by other means, such as heating or cooling. We have studied the settling of particles through a stratified ambient, and a current focus is on the dynamics of sediment-laden plumes and their application to deep-water mining activities.

Funding for our research comes from the NSF and MIT Environmental Solutions Initiative.


Sailing on Natural Convection

When a homogeneous fluid is heated (or cooled) at an inclined surface, a boundary-layer flow develops along the surface that is driven by buoyancy effects due to the change of density with temperature. We have designed a triangular wedge immersed in a fluid with one of his boundaries being a heated plate, and showed that this macroscopic object moves at a constant speed when heating is on. We also predict the speed of the wedge by balancing the drag with the propulsion force obtained by the analytical description of the boundary-layer laminar flow. This effect has potentially widespread application to topics as diverse as bioengineering, microfluidics and geosciences. A detailed report of this study has been published in Physical Review Letters. [read the paper]

Relevant Publications

  1. Blanchette, F., Peacock, T. and Bush J.W.M., "The Boycott effect in magma chambers," Geophysical Research Letters, 31, L05611 (2004). [link]
  2. Peacock, T., Stocker, R. and Aristoff, J., "An experimental investigation of the angular dependence of diffusion-driven flow," Physics of Fluids, 16, 3503-3505, (2004). [link]
  3. Peacock, T., Blanchette, F. and Bush J.W.M., "The stratified Boycott effect," Journal of Fluid Mechanics, 529, 33-49 (2005). [link]
  4. Heitz, R., Peacock, T. and Stocker, R., "Optimizing diffusion-driven flow in a fissure," Physics of Fluids, 17, Art. No. 128104 (2005). [link]
  5. Yick, K.Y., Stocker, R. and Peacock, T., "Microscale Synthetic Schlieren," Experiments in Fluids, 42 (1), 41-48 (2007). [link]
  6. Blanchette, F., Peacock, T. and Cousin, R., "Stability of a stratified fluid with a vertically moving sidewall," Journal of Fluid Mechanics, 609, 305-317 (2008). [link]
  7. Yick, K.Y., Torres, C.R., Peacock, T. and Stocker, R., "Enhanced drag of a sphere settling in a stratified fluid at small Reynolds number," Journal of Fluid Mechanics, 632, 49-68 (2009). [link]
  8. Allshouse, M.R., Barad, M.F. and Peacock, T., "Propulsion generated by diffusion-driven flow," Nature Physics, 6, 516 (2010). [link]
  9. Mercier, M., Ardekani, A., Allshouse, M. R., Doyle, B., and Peacock, T., "Self-Propulsion of Immersed Objects via Natural Convection," Physical Review Letters, 112, 204501 (2014).[link]


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