Research output: Contribution to journal › Article › peer-review
Internal wave attractors in three-dimensional geometries : Trapping by oblique reflection. / Pillet, G.; Ermanyuk, E. V.; Maas, L. R.M. et al.
In: Journal of Fluid Mechanics, Vol. 845, 25.06.2018, p. 203-225.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Internal wave attractors in three-dimensional geometries
T2 - Trapping by oblique reflection
AU - Pillet, G.
AU - Ermanyuk, E. V.
AU - Maas, L. R.M.
AU - Sibgatullin, I. N.
AU - Dauxois, T.
PY - 2018/6/25
Y1 - 2018/6/25
N2 - We study experimentally the propagation of internal waves in two different three-dimensional (3D) geometries, with a special emphasis on the refractive focusing due to the 3D reflection of obliquely incident internal waves on a slope. Both studies are initiated by ray tracing calculations to determine the appropriate experimental parameters. First, we consider a 3D geometry, the classical set-up to get simple, two-dimensional (2D) parallelogram-shaped attractors in which waves are forced in a direction perpendicular to a sloping bottom. Here, however, the forcing is of reduced extent in the along-slope, transverse direction. We show how the refractive focusing mechanism explains the formation of attractors over the whole width of the tank, even away from the forcing region. Direct numerical simulations confirm the dynamics, emphasize the role of boundary conditions and reveal the phase shifting in the transverse direction. Second, we consider a long and narrow tank having an inclined bottom, to simply reproduce a canal. In this case, the energy is injected in a direction parallel to the slope. Interestingly, the wave energy ends up forming 2D internal wave attractors in planes that are transverse to the initial propagation direction. This focusing mechanism prevents indefinite transmission of most of the internal wave energy along the canal.
AB - We study experimentally the propagation of internal waves in two different three-dimensional (3D) geometries, with a special emphasis on the refractive focusing due to the 3D reflection of obliquely incident internal waves on a slope. Both studies are initiated by ray tracing calculations to determine the appropriate experimental parameters. First, we consider a 3D geometry, the classical set-up to get simple, two-dimensional (2D) parallelogram-shaped attractors in which waves are forced in a direction perpendicular to a sloping bottom. Here, however, the forcing is of reduced extent in the along-slope, transverse direction. We show how the refractive focusing mechanism explains the formation of attractors over the whole width of the tank, even away from the forcing region. Direct numerical simulations confirm the dynamics, emphasize the role of boundary conditions and reveal the phase shifting in the transverse direction. Second, we consider a long and narrow tank having an inclined bottom, to simply reproduce a canal. In this case, the energy is injected in a direction parallel to the slope. Interestingly, the wave energy ends up forming 2D internal wave attractors in planes that are transverse to the initial propagation direction. This focusing mechanism prevents indefinite transmission of most of the internal wave energy along the canal.
KW - geophysical and geological flows
KW - internal waves
KW - stratified flows
KW - ENERGY
KW - INSTABILITY
KW - OCEAN
KW - RECTANGULAR BASIN
KW - ONE SLOPING BOUNDARY
KW - EMPIRICAL MODE DECOMPOSITION
KW - FLUID
KW - SPECTRUM
KW - PROPAGATION
KW - INERTIAL WAVES
UR - http://www.scopus.com/inward/record.url?scp=85045767157&partnerID=8YFLogxK
U2 - 10.1017/jfm.2018.236
DO - 10.1017/jfm.2018.236
M3 - Article
AN - SCOPUS:85045767157
VL - 845
SP - 203
EP - 225
JO - Journal of Fluid Mechanics
JF - Journal of Fluid Mechanics
SN - 0022-1120
ER -
ID: 12799636