Internal Wave Kinetic Energy: Particle Imaging Velocimetry vs Synthetic Schlieren*

Internal waves generated throughout the ocean significantly impact the ocean energy budget. Historically, Particle Image Velocimetry (PIV) has been an extensively used experimental method for analyzing internal waves and propagating wave power. Synthetic Schlieren (SS) methods have mostly been used only to estimate the change in natural frequency (N). If SS methods can be used in place of PIV methods for internal wave energy analysis, the cost will decrease and the ease of computing will increase. The kinetic energy values of internal waves generated by an excitation frequency (ω) were computed using SS, using the models outlined by Lee and Crockett, and Wunsch and Brandt, for evanescent (N < ω) and propagating (N > ω) waves respectively. The results from the SS methods compared well with the results obtained from PIV.  The experiments performed were focused on the kinetic energy generated from varying topographies and local density stratification profiles.