THE ROLE OF EROSION AT THE HEAD OF SUSPENSION CURRENTS EXPERIMENT AND THEORY Cian Carroll, B' Turnbu

1
THE ROLE OF EROSION AT THE HEAD OF SUSPENSION
CURRENTSEXPERIMENT AND THEORYCian Carroll, B.
Turnbull, M.Y. Louge and E.A. Cowen School of
Mechanical and Aerospace Engineering, Cornell
University, Ithaca, NY 14853

• Suspension currents are ubiquitous in nature,
  including avalanches, sand storms and deep-sea
  sediment slides. They self-sustain by eroding
  particles from the ground, thus maintaining a
  density difference with the surrounding clear
  fluid. We investigate them with experiments and
  theory. Our goal is to predict how the
  characteristic shape of the current's head
  changes with the density difference at various
  rates of basal erosion, which we model as an
  isotropic source of fluid with a different
  density.

The top figure illustrates how the classical
Rankine half body solution for same density
fluids is affected by a 1 density difference
between source and uniform stream. We calculate
the perturbation to the current's head shape and
to velocities and pressures within the advancing
front. We recently recorded this photograph in a
newly designed flume.