by Staff Writers Washington DC (SPX) Nov 20, 2012 A new approach
to invisibility cloaking may one day be used at sea to shield
floating objects - such as oil rigs and ships - from rough
waves. Unlike most other cloaking techniques that rely on
transformation optics, this one is based on the influence of the
ocean floor's topography on the various "layers" of ocean water.
At the American Physical Society's (APS) Division of Fluid
Dynamics (DFD) meeting Reza Alam, assistant professor of
mechanical engineering at the University of California,
Berkeley, will describe how the variation of density in ocean
water can be used to cloak floating objects against incident
surface waves. "The density of water in an ocean or sea
typically isn't constant, mainly because of variations in
temperature and salinity," explains Alam. "Solar radiation heats
the upper layer of the water, and the flow of rivers and the
melting of ice lowers the water density near the surface. Over
time, these effects add up to form a stable density