caa a22 4500 606198660 CHVBK 20210128100935.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s00348-015-1954-2 doi (NATIONALLICENCE)springer-10.1007/s00348-015-1954-2 Experimental study of nonlinear harmonic generation by internal waves incident on a pycnocline [Elektronische Daten] [Scott Wunsch, Ian Delwiche, Gary Frederick, Alan Brandt] Internal waves propagating in variable stratification exhibit nonlinear generation of harmonics. Here, synthetic schlieren is used to study a laboratory internal wave beam propagating from a uniformly stratified layer into a region of increased stratification (pycnocline) below a mixed layer. The results demonstrate the formation of harmonic (double-frequency) internal waves as the beam refracts into the pycnocline layer. For beam incidence angles <30° to the horizontal, harmonic internal waves are radiated back to the uniformly stratified layer. The harmonic wavenumber is approximately double the incident wavenumber, while its amplitude increases with the pycnocline buoyancy frequency gradient. Beams with larger incidence angles generate harmonics that are trapped within the pycnocline layer. In this case, the specific wavenumber of the trapped harmonic is determined by the normal modes of the stratification profile. Springer-Verlag Berlin Heidelberg, 2015 Wunsch Scott Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, USA aut Delwiche Ian Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, USA aut Frederick Gary Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, USA aut Brandt Alan Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, USA aut Experiments in Fluids Springer Berlin Heidelberg 56/5(2015-05-01), 1-14 0723-4864 56:5<1 2015 56 348 https://doi.org/10.1007/s00348-015-1954-2 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00348-015-1954-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wunsch Scott Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, USA aut NATIONALLICENCE 700 1- Delwiche Ian Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, USA aut NATIONALLICENCE 700 1- Frederick Gary Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, USA aut NATIONALLICENCE 700 1- Brandt Alan Applied Physics Laboratory, The Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, USA aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/5(2015-05-01), 1-14 0723-4864 56:5<1 2015 56 348