| Résumé: | <p>This thesis examines Lagrangian-mean flows induced by surface gravity waves, with
particular emphasis on the displacements associated with these flows. Stokes drift,
the small Lagrangian-mean velocity accompanying the orbital motion of particles
beneath surface waves, has been well-studied, and is proven to play a role in ocean
transport. However, Eulerian-mean flows induced by slow variation of the wave
field (divergence-driven), viscous effects, or geophysical effects such as density
stratification and planetary rotation, have received less attention. It is the aim
of this thesis to study these wave-induced Eulerian-mean flows, which must be
superimposed on the Stokes drift to obtain the correct Lagrangian-mean (or mass
transport) velocity induced by surface gravity waves. In Chapter 2, the effects of
wave directional spread and density stratification on the mean flow induced by
a surface gravity wavepacket in deep water are studied, and the corresponding
displacements are derived. Chapter 3 examines ‘Ekman–Stokes’ dynamics driven
by the Stokes drift and Coriolis force within the turbulent upper ocean boundary
layer, and uses buoy data to explore the impact these dynamics have on the drift of
a floating particle. Finally, in Chapter 4 I combine the insights of the two previous
chapters to develop an analytical model capable of describing both divergence-driven and geophysically-driven Eulerian-mean flows induced by surface waves.</p>
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