Propagation and breaking of nonlinear internal gravity waves

• Author / Creator

  Dosser, Hayley V

• Internal gravity waves grow in amplitude as they propagate upwards in a non-Boussinesq fluid and weakly nonlinear effects develop due to interactions with an induced horizontal mean flow. In this work, a new derivation for this wave-induced mean flow is presented and nonlinear Schrodinger equations are derived describing the weakly nonlinear evolution of these waves in an anelastic gas and non-Boussinesq liquid. The results of these equations are compared with fully nonlinear numerical simulations. It is found that interactions with the wave-induced mean flow are the dominant mechanism for wave evolution. This causes modulational stability for hydrostatic waves, resulting in propagation above the overturning level predicted by linear theory for a non-Boussinesq liquid. Due to high-order dispersion terms in the Schrodinger equation for an anelastic gas, hydrostatic waves become unstable and break at lower levels. Non-hydrostatic waves are modulationally unstable, overturning at lower levels than predicted by linear theory.

• Subjects / Keywords

  • Anelastic
  • Atmosphere
  • Schrodinger
  • Modulational
  • Non-Boussinesq
  • Nonlinear
  • Internal gravity wave

• Graduation date

  Spring 2010

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3XQ5C

• 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.