Time: 3:30pm, Tuesday, October 7, 2008
Place: CEB Room 4-42
Title: Internal Wave Beam Propagation in Nonlinear
Stratifications
Presenter
Thomas Peacock
Dept. Mechanical Engineering, MIT
Abstract:
In addition to being observable in laboratory experiments, internal wave beams are commonly reported in oceanic and atmospheric settings, which are characterized by nonuniform stratifications. We build upon prior studies of plane waves to investigate the propagation of linear internal wave beams in nonlinear density stratifications, in the absence of shear. Analytical expressions are obtained for transmission and reflection coefficients of wave beams across sharp and finite-width interfaces. These coefficients can differ greatly for different physical quantities associated with an internal wave, such as velocity, density gradient or energy-flux; giving alternative realizations depending on the quantity under investigation. Under certain conditions, which do not necessitate evanescent layers, wave beam ducting occurs. Results from lab experiments complement the theoretical predictions, and we discuss applications to the ocean and atmosphere.