I am always fascinated by the rare but extremely large waves occurring in the open ocean. These gigantic waves are observed globally in the ocean but the nonlinear physics behind them varies at different locations. I am interested in all of these nonlinear physics that could potentially lead to a rogue wave in the ocean: Modulational Instability, Wave travelling over variable bathymetry, Wave current interactions, Wind wave interactions, Directionality of wave fields, Wave breaking etc. 

There is no new wave, only the sea. 

- by Claude Chabrol 

Modulational instability

Figure 1: Spatial evolution of kurtosis for (a) experimental results and numerical simulations compared against theoretical curves, (b) experimental facilities, and (c) maximum kurtosis reached for different bandwidths and steepness. (d) proposed analytical predictions in finite water compared against simulations. (T. Tang 2020, T. Tang 2021)

Figure 2: Average shape of extreme events for (a): unidirectional waves travelling along the numerical tank compared to (b): theoretical predictions. The horizontal asymmetry of extreme events for naturally occurring water waves, (c) for the lake George dataset and (d) for the North Sea dataset. The envelope fronts of extreme events are presented in filled dots and the envelope tails are presented in triangles. (T. Tang 2019, T. Tang 2020) 

High-frequency tails

We find that curtailing the spectrum can have a significant impact on the subsequent evolution. In particular, for cases where the spectrum has been curtailed, the non-linear physics produces significantly more extreme or rogue waves than are observed in the case where the full spectral tail was included in the initial conditions, and this difference persists over 10s of periods after
the waves are initialised.

Figure 3: Kurtosis evolution for O09ST (red line) and O09LT (blue line) compared against other studies. (T. Tang 2022)

Wave topography 

Abrupt changes in water depth are known to lead to abnormal free surface wave statistics. The present study considers whether this translates into abnormal loads on offshore infrastructure.

Figure 4: Total velocity (m/s) at the different horizontal and vertical locations. x and z represent horizontal and vertical locations. The magnitude of the total velocity corresponds to different colours, shown in the colour bar. (Z. Li, T. Tang et. al. 2022)