Internal wave tunnelling: Laboratory experiments

• Author / Creator

  Gregory, Kate D

• Heuristics based upon ray theory are often used to predict the propagation of internal gravity waves in non-uniform media. In particular, they predict that waves reflect from weakly stratified regions where the local buoyancy frequency is less than the wave frequency. However, if the layer of weak stratification is sufficiently thin, waves can partially transmit through it in a process called tunnelling. The first laboratory evidence of internal wave tunnelling through a weakly stratified region is analysed using the synthetic schlieren technique and the Hilbert transform is applied to filter the wavefield into upward- and downward-propagating components. Transmission is calculated as the squared ratio of transmitted and incident wave amplitude and using an appropriate superposition of plane waves to reproduce the structure of the incident wave beam, a corresponding weighted sum of transmissions can be used to predict the beam transmission. These transmission predictions are compared with experimental measurements.

• Subjects / Keywords

  • Internal
  • Waves
  • Tunnelling

• Graduation date

  Spring 2010

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R33706

• 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.