1. Modified Stokes drift due to the interactions between surface wave and bottom topography [paper link]
A monochromatic rightward propagating wave drifts a parcel in its direction of propagation; the mechanism at play is Stokes drift. Their interaction with a corrugated bottom yields a reflected wave, and this complex interference is known as the Bragg resonance mechanism. The generation of reflected wave modifies the surface wave and affects the particle motion, which depends on the particle's location with respect to bottom ripples. It shows that a corrugated patch of bottom topography can act as a non-surface invasive pollutant trap. This can help in designing artificial patches of bottom topography for mitigating marine pollution like microplastics, oil particles, and chemicals. I have also developed high-order spectral method code in MATLAB to accurately capture nonlinear resonant interactions between SGW and corrugated bottom topography (2D and 3D).
The presence of bottom topography and background current leads to a non-homogeneous system of equations. The theoretical analysis reveals that such non-homogeneity generates steady surface imprints, which leads to a novel mass transport mechanism analogous to the celebrated Stokes drift by surface gravity waves (figure b). This new drift is referred to as current-bathymetry interaction induced drift (CBIID), as shown in figure (c). Hence, in addition to the Stokes drift, this new mass transport mechanism needs to be factored in for the accurate prediction of tracer transport pathways in fluvial and coastal environments.
Surface gravity wave analogues are used to understand the classical features of black holes. The idea in our analogy is that confined surface gravity wave packets act as virtual particles. We propose a minimal analogue gravity setup and suggest how to select two surface gravity wave packets to mimic the classical feature of Hawking radiation from the horizon of non-rotating black holes. Our proposed setup constitutes a constant mean flow over a flat bathymetry, in which the two wave packets possess the same amount of wave action but equal and opposite (sign) amount of energy, thereby mimicking virtual particles created out of near horizon vacuum fluctuations.
