Internal wave generation by intrusions, topography, and turbulence

  • Author / Creator
    Munroe, James Ross
  • Internal gravity waves transport energy and momentum in both the atmosphere and the ocean. This physical process occurs at such small length scales that it is not captured by coarse resolution numerical models of weather and climate. A series of experiments is presented that model the generation of non-hydrostatic internal gravity waves by intrusions and by the forcing of wind driven turbulent eddies in the surface mixed layer of the ocean. In a first set of experiments, gravity currents intrude into a uniformly stratified ambient fluid and the internal waves that are launched are examined with a finite-volume, full-depth, lock-release setup. In a second set of experiments, isolated rough topography is towed through stratified fluid and the interaction between the turbulent wake and internal waves is investigated. In a third set of experiments, a turbulent shear layer is forced by a conveyor belt affixed with flat plates near the surface of a stratified fluid and downward propagating internal waves are generated. The turbulence in the shear layer is characterized using particle image velocimetry to measure the kinetic energy as well as length and time scales. The internal waves are measured using synthetic schlieren to determine the amplitudes, frequencies, and the energy of the generated waves. Finally, numerical simulations are used to validate and extend the results of laboratory experiments. The thesis will address the question of what fraction of the turbulent kinetic energy of a shear turbulent mixed layer is radiated away by internal waves. Implications for internal waves propagating into the ocean are discussed.

  • 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.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
  • Supervisor / co-supervisor and their department(s)
  • Examining committee members and their departments
    • Heimpel, Moritz (Physics)
    • Wilson, John (Earth & Atmospheric Sciences)
    • Kravchinsky, Vadim (Physics)
    • Peacock, Thomas (Mechanical Engineering, Massachusetts Institute of Technology)
    • Myers, Paul (Earth & Atmospheric Sciences)