Disputas: Huiming Zeng

M. Eng. Huiming Zeng ved Matematisk institutt vil forsvare sin avhandling for graden ph.d.: 

Evolution of statistics of weakly nonlinear unidirectional waves over a sloping bottom

 

Huiming Zeng

Tid og sted for prøveforelesning 

2. november 2012 kl. 10.15,  Abels Utsikt, 12. et., Niels Henrik Abels hus.

Bedømmelseskomité

  • Professor Tarmo Soomere, Institute of Cybernetics, Tallinn University of Technology

  • Professor John Andreas Wyller, Department of Mathematical Sciences and Technology, UMB
  • Associate Professor, Mikael Mortensen, Matematisk institutt, Universitet i Oslo

Leder av disputas

Professor Atle Jensen, Matematisk institutt, Universitet i Oslo

Veiledere

Sammendrag

Freak or rogue waves are waves that are much higher than expected for the sea state, and they are a threat to ships and platform, causing accidents resulting in human loss. Thus, the understanding of freak waves is of great importance to help us decide proper designs and operations of marine structures in off-shore waters and safeguard coastal regions.

The work in the thesis focuses on wave forecasting in waters of non-uniform depth, particularly investigating how the probability of freak waves  is affected by shoaling. In order to solve the problem, we carried out statistical analysis of results from both numerical simulations of nonlinear models and experiments. We found evidence that a local change in bathymetry may provoke non-equlibrium statistics in a region that may extend far beyond the local depth nonuniformity. Furthermore, in finite water depth, the kurtosis decreases toward the shallower side and there can be a local minimum of kurtosis after the slope. In shallow water, there can be a local maximum of kurtosis near the shallow side of the slope.  Therefore, as an application, we anticipate that the probability of freak waves on or near the edge of the continental shelf may exhibit a rather complicated spatial structure.
 

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Publisert 18. okt. 2012 13:50 - Sist endret 17. okt. 2014 13:56