Lab Home | Phone | Search
Center for Nonlinear Studies  Center for Nonlinear Studies
 Colloquia Archive 
 Postdoc Seminars Archive 
 Quantum Lunch 
 Quantum Lunch Archive 
 CMS Colloquia 
 Q-Mat Seminars 
 Q-Mat Seminars Archive 
 P/T Colloquia 
 Kac Lectures 
 Kac Fellows 
 Dist. Quant. Lecture 
 Ulam Scholar 
 CNLS Fellowship Application 
 Student Program 
 Past Visitors 
 History of CNLS 
 Maps, Directions 
 CNLS Office 
Tuesday, November 27, 2012
1:00 PM - 2:00 PM
CNLS Conference Room (TA-3, Bldg 1690)


Mixing by waves in a stratified fluid

Philippe Odier
Laboratoire de Physique, Ecole Normale Superieure de Lyon

Internal waves are believed to be of primary importance as they affect ocean mixing and energy transport. Several processes can lead to the breaking of internal waves and they usually involve non linear interactions between waves. In this work, we study experimentally the Parametric Subharmonic Instability (PSI), which provides an efficient mechanism to transfer energy from large to smaller scales. It consists in the destabilization of a primary wave and the spontaneous emission of two secondary waves, of lower frequencies and different wave vectors. Using a time-frequency analysis, we observe the time evolution of the secondary waves, thus measuring the growth rate of the instability. In addition, a Hilbert transform method allows us to measure the different wave vectors. We compare these measurements with theoretical predictions, and study the dependance of the instability with primary wave frequency and amplitude. In addition we will present a preliminary study of how internal waves can produce mixing in the stratified fluid, and how this mixing is enhanced by the presence of PSI.

Host: Robert Ecke, CNLS, 667-1444,