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Researcher Controls Rogue Waves in the Lab

By MarEx 2016-09-30 22:10:31

Rogue waves are unusually large surface waves that occur in the ocean. People have usually reported them as having appeared suddenly or without warning, sometimes with tremendous force. A researcher from Aalto University in Finland has now developed a laboratory method for generating them under realistic oceanic conditions.

“Potentially extremely dangerous realistic rogue waves can now be controlled and generated at will in laboratory environments, in similar conditions as they appear in the ocean,” says Professor Amin Chabchoub from Aalto University. “This will help us not only to predict oceanic extreme events, but also in the design of safer ships and offshore rigs. In fact, newly designed vessels and rig model prototypes can be tested to encounter in a small scale, before they are built, realistic extreme ocean waves. Therefore, initial plans may change, if models are not resistant enough to face suddenly occurring freak waves.”

The birth of rogue waves can be physically explained through the modulation instability of water waves.  In mathematical terms, this phenomenon can be described through exact solutions of the nonlinear Schrödinger equation. 

For a couple of years, the research team around Professor Chabchoub has already been able to create steered rogue waves in laboratory wave flumes. However, this has only succeeded in perfect regular wave conditions. In nature, this is rarely the case.

Prediction Tool

A prediction tool was developed by MIT engineers earlier this year that may give sailors a two to three minute warning of an incoming rogue wave, hopefully providing them with enough time to shut down essential operations on a ship or offshore platform.

The tool, in the form of an algorithm, sifts through data from surrounding waves to spot clusters of waves that may develop into a rogue wave. Depending on a wave group’s length and height, the algorithm computes a probability that the group will turn into a rogue wave within the next few minutes.

Mysterious Loss

The 260-meter long German barge carrier MS München was lost mysteriously at sea in 1978. The final communication message was a garbled mayday message sent from the mid-Atlantic. Afterwards, only a few bits of wreckage were found, including an unlaunched lifeboat. The most accepted theory is that one or more rogue waves hit the MS München and damaged her.

Recent Events

MS Bremen and Caledonian Star (South Atlantic, 2001) encountered 30-meter (98 feet) freak waves. Bridge windows on both ships were smashed, and all power and instrumentation lost.

U.S. Naval Research Laboratory ocean-floor pressure sensors detected a freak wave caused by Hurricane Ivan in the Gulf of Mexico, 2004. The wave was around 27.7 meters (91 feet) high from peak to trough and around 200 meters (660 feet) long.

On April 16, 2005, after sailing into rough weather off the coast of Georgia, Norwegian Dawn encountered a series of three 70-foot (21 meter) rogue waves. The third wave damaged several windows on the 9th and 10th decks and several decks were flooded. Damage, however, was not extensive and the ship was quickly repaired. Four passengers were slightly injured in this incident.

Footage of Aleutian Ballad, (Bering Sea, 2005) in what is identified as a 60-foot (18 meter) wave appears in an episode of Deadliest Catch. The wave strikes the ship at night and cripples the vessel, causing the boat to tip for a short period onto its side. This is one of the few video recordings of what might be a rogue wave.

In 2006, researchers from U.S. Naval Institute theorize rogue waves may be responsible for the unexplained loss of low-flying aircraft, such as U.S. Coast Guard helicopters during search and rescue missions.

On January 24, 2009 the Augusto González de Linares buoy, located 22 miles north of Santander, Spain reported a wave of 26.13 meters, equivalent to 8 floors high, during a storm.

MS Louis Majesty (Mediterranean Sea, March 2010) was struck by three successive 8-metre (26 feet) waves while crossing the Gulf of Lion on a Mediterranean cruise between Cartagena and Marseille. Two passengers were killed by flying glass when a lounge window was shattered by the second and third waves. The waves, which struck without warning, were all abnormally high in respect to the sea swell at the time of the incident.

The Spanish Deepwater Buoys Network, in January 2014, measured a wave height of 27.81 meters (91.2 feet). The data was taken at the buoy Vilán-Sisargas (Cape Vilan) in Galicia (Spain) during the winter storms, which were particularly severe in Atlantic waters.

MS Marco Polo was struck by a rogue wave in the English Channel (February 2014), and killed a 85-year-old man and injured a woman in her 70s.