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Interfacial instabilities in sediment suspension flows

Abedi, M ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1017/jfm.2014.531
  3. Abstract:
  4. We report the existence of interfacial instability in the two-dimensional channel flow of a sediment suspension whose particles diffuse in the carrier fluid due to shear-induced collisions. We derive partial differential equations that govern the deformations of the interface between the sediment suspension and the clear fluid, and devise a perturbation method that preserves the positivity of the particle volume fraction. We solve perturbed momentum, particle transport and deforming interface equations to show that a Kelvin-Helmholtz-type unstable wave develops at the interface for wavelengths longer than a critical value. Short-wavelength oscillations of the interface are damped due to shear-induced diffusion of particles. We also show that the lowest critical Reynolds number, above which the interface is unstable, occurs for intermediate values of the total volume fraction of particles
  5. Keywords:
  6. Instability ; Multiphase and particle-laden flows ; Deformation ; Differential equations ; Diffusion in liquids ; Perturbation techniques ; Plasma stability ; Reynolds number ; Shear flow ; Suspended sediments ; Volume fraction ; Critical Reynolds number ; Interface equations ; Interfacial instability ; Particle volume fractions ; Perturbation method ; Shear-induced diffusion ; Two-dimensional channel flow ; Suspensions (fluids) ; Channel flow ; Multiphase flow ; Oscillating flow
  7. Source: Journal of Fluid Mechanics ; Vol. 758, issue , November , 2014 , p. 312-326
  8. URL: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9375584&fileId=S002211201400531X