Researchers at the City College of New York say they have developed a new way to generate power for planes and automobiles using piezoelectrics.  Piezoelectrics convert the kinetic energy of motion into electricity. The researchers will present their concept later this month at the 62nd Annual Meeting of the American Physical Society's (APS) Division of Fluid Dynamics.

About a half-inch by one inch in size, these devices could be mounted on the roof or tail of a car or on an airplane fuselage where they would vibrate inside a flow, producing an output voltage. The power generated would not be enough to replace that supplied by the combustion engines, but it could run some systems such as batteries that would be used to charge control panels and other small electronic devices such as mobile phones. 

The researchers are currently attempting to optimize these devices by modeling the physical forces to which they are subjected in different air flows -- on the roof of a car, for instance, or on the back of a truck. 

When the device is placed in the wake of a cylinder -- such as on the back of a truck -- the flow of air will cause the devices to vibrate in resonance, says Andreopoulos. On the roof of car, they will shake in a much more unsteady flow known as a turbulent boundary layer.  The researchers will present wind tunnel data showing how the devices work in both situations.

"These devices open the possibility to continuously scavenge otherwise wasted energy from the environment," says CCNY professor Yiannis Andreopoulos.