Dam-break flows as agents of sediment transport

• Author / Creator

  Emmett, Matthew

• When a semi-infinite body of homogeneous fluid initially at rest
  behind a vertical retaining wall is suddenly released by the removal
  of the barrier the resulting flow over a horizontal or sloping bed
  is referred to as a dam-break flow. When resistance to the flow is
  neglected the exact solution, in the case of a stable horizontal bed
  with or without `tail water', may be obtained on the basis of
  shallow-water theory via the method of characteristics and the
  results are well known. Discrepancies between these shallow-water
  based solutions and experiments have been partially accounted for by
  the introduction of flow resistance in the form of basal friction.
  This added friction significantly modifies the wave speed and flow
  profile near the head of the wave so that the simple exact solutions
  no longer apply and various asymptotic or numerical approaches must
  be implemented to solve these frictionally modified depth-averaged
  shallow-water equations. When the bed is no longer stable so that
  solid particles may be exchanged between the bed and the water
  column the dynamics of the flow becomes highly complex as the
  buoyancy forces vary in space and time according to the competing
  rates of erosion and deposition. Furthermore, when the Froude
  number of the flow is close to unity perturbations in the height and
  velocity profiles grow into N-waves and the bed below develops
  ripples which act to sustain the N-waves in the fluid above. It is
  our intention here to study dam-break flows over erodible sloping
  beds as agents of sediment transport taking into account basal
  friction as well as the effects of particle concentrations on flow
  dynamics including both erosion and deposition. We shall consider
  shallow flows over initially dry beds and investigate the effects of
  changes in the depositional and erosional models employed as well as
  in the nature of the drag acting on the flow and the slope of the
  bed. These models include effects hitherto neglected in such
  studies and offer insights into the transport of sediment in the
  worst case scenario of the complete and instantaneous collapse of a
  dam.

• Subjects / Keywords

  • Dam-break
  • sediment transport
  • WENO
  • N-wave

• Graduation date

  Fall 2010

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3D63S

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.