Predicting the occurrence and behaviour of large waves

Modelling oceanic waves to enhance marine and naval practices

Large-amplitude internal solitary waves commonly occur in the interior of the ocean. Their associated currents impact marine platforms, shipping, underwater pipelines and submersibles. They also have a severe impact on acoustic signalling.

Interaction of the tide with prominent features at the bottom of the ocean leads to the formation of an internal tide, which evolves into a train of very large-amplitude internal waves with associated high density displacements and strong currents.

It is essential for marine engineers, ship operators and naval scientists concerned with the effect of these waves on offshore structures and submersibles to have a comprehensive understanding of their likely behaviour and impact.

Research on internal solitary waves in the coastal ocean is a very active area, conducted worldwide by physical oceanographers and marine engineers. Intensive observations have been obtained in several locations by ship-based experiments, supplemented by global satellite observations.

Theoretical modelling has been based either on numerical simulations or on the development of analytical models.

Research conducted in the Department of Mathematical Sciences has made a major contribution to the latter.

The research has focussed on four main areas – generation mechanisms, the structure of internal wave trains, the effect of bottom topography, and the role of the earth’s rotation.

One of the main thrusts of the research has been the investigation of how internal solitary waves deform – and possibly even disintegrate – as they propagate over variable topography. One of the outcomes of this research is that a new modelling paradigm for non-linear oceanic waves has been developed.

NEW TOOLS: The analytical models developed have provided new tools for marine engineers and ship operators worldwide.
PREDICTING THE EFFECT OF LARGE WAVES: Oil companies – such as BP, Exxon Mobil and StatOil – have benefitted from this research as working offshore needs the capacity to predict the occurrence of these large waves and to assess the impact of waves on structures and pipe lines.
ACOUSTIC COMMUNICATIONS: Submersibles routinely communicate using sound signals which are hugely distorted by internal waves. For this reason the US Navy, through the Office of Naval Research, has conducted several major ocean experiments, using theory first developed at Loughborough.
WIDESPREAD USE: Loughborough’s research means that that an extended and modified model for theoretical interpretation is now routinely used around the world as the basic paradigm for the dynamical understanding of the nonlinear internal waves commonly found in the coastal oceans.