TY - JOUR

T1 - Particle dispersion by random waves in rotating shallow water

AU - Bühler, Oliver

AU - Holmes-Cerfon, Miranda

N1 - Funding Information:
We thank Raffaele Ferrari for sharing with us an unpublished manuscript on a similar problem. Kelly Sielert performed and analysed some numerical simulations of particle trajectories as part of an undergraduate research experience. Financial support for this work under the United States National Science Foundation grant DMS-0604519 is gratefully acknowledged. M. H. C. is supported in part by a Canadian NSERC PGS-D scholarship.

PY - 2009/11

Y1 - 2009/11

N2 - We present a theoretical and numerical study of wave-induced particle dispersion due to random waves in the rotating shallow-water system, as part of an ongoing study of particle dispersion in the ocean. Specifically, the effective particle diffusivities in the sense of Taylor (Proc. Lond. Math. Soc., vol. 20, 1921, p. 196) are computed for a small-amplitude wave field modelled as a stationary homogeneous isotropic Gaussian random field whose frequency spectrum is bounded away from zero. In this case, the leading-order diffusivity depends crucially on the nonlinear, second-order corrections to the linear velocity field, which can be computed using the methods of wavemean interaction theory. A closed-form analytic expression for the effective diffusivity is derived and carefully tested against numerical Monte Carlo simulations. The main conclusions are that Coriolis forces in shallow water invariably decrease the effective particle diffusivity and that there is a peculiar choking effect for the second-order particle flow in the limit of strong rotation.

AB - We present a theoretical and numerical study of wave-induced particle dispersion due to random waves in the rotating shallow-water system, as part of an ongoing study of particle dispersion in the ocean. Specifically, the effective particle diffusivities in the sense of Taylor (Proc. Lond. Math. Soc., vol. 20, 1921, p. 196) are computed for a small-amplitude wave field modelled as a stationary homogeneous isotropic Gaussian random field whose frequency spectrum is bounded away from zero. In this case, the leading-order diffusivity depends crucially on the nonlinear, second-order corrections to the linear velocity field, which can be computed using the methods of wavemean interaction theory. A closed-form analytic expression for the effective diffusivity is derived and carefully tested against numerical Monte Carlo simulations. The main conclusions are that Coriolis forces in shallow water invariably decrease the effective particle diffusivity and that there is a peculiar choking effect for the second-order particle flow in the limit of strong rotation.

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U2 - 10.1017/S0022112009991091

DO - 10.1017/S0022112009991091

M3 - Article

AN - SCOPUS:76349104446

SN - 0022-1120

VL - 638

SP - 5

EP - 26

JO - Journal of Fluid Mechanics

JF - Journal of Fluid Mechanics

ER -