Experimental Investigation of Ice Floe Stability

  • Author / Creator
    Ambtman, Karen Elizabeth Dow
  • It is known that discrete ice floes approaching an ice cover from upstream will either contribute to the lengthening of the ice cover, or will become entrained in the flow. Knowledge of the hydrodynamic forces acting on individual ice floes is an important component of any model attempting to predict ice cover progression. Currently ice process models rely on empirical relationships to predict the behaviour of ice floes at the leading edge of an intact ice cover.

    Experimental studies were conducted in a re-circulating flume in the T. Blench Hydraulics Laboratory at the University of Alberta to increase the knowledge of the physical behaviour of ice floes in water, and the hydrodynamic forces that act upon them. The dynamic pressure was measured beneath a floating “ice” block for various block thickness-to-depth ratios and flow velocities and leading edge shapes. The effect of block rotation on the resulting pressure distribution was also investigated by tilting the block until its top upstream corner reached the water surface. Digital particle image velocimetry was used also to characterize the velocity field beneath a floating ice block investigating the effect of block thickness and leading edge shape on the resulting velocity field.

    A method was developed for predicting the pressure distribution beneath a floating ice block and as well as the submerging forces and moments. A stability analysis was performed to determine the conditions under which a floating block would become entrained through a force – moment analysis. The velocity field revealed a separation zone forms at the leading edge of the rectangular block which was eliminated by rounding the leading edge of the block. The velocity results were found to be correlated with the resulting pressure reduction beneath the block. This confirms the importance of localized flow behaviour due to flow acceleration and separation on the stability of a block.

    The work presented in this thesis presents the first rigorous method for determining ice block stability based on actual flow physics and the first detailed characterization of the velocity field beneath a floating ice block.

  • Subjects / Keywords
  • Graduation date
    Fall 2009
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • 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.