Using Aerospace Approach, Engineers Design Wave Energy System

Friday, November 20 2009

Aerospace engineers from the U.S. Air Force Academy are applying the principles that keep airplanes aloft to create a new wave energy system that is durable, efficient, and can be placed anywhere in the ocean - regardless of depth. While still in early design stages, computer and scale-model tests of the system suggest higher efficiencies than wind turbines.

The system is designed to effectively cancel incoming waves - capturing their energy while flattening them out - providing an added application as a storm-wave breaker.

"Our group was working on very basic research on feedback flow control for years," says lead researcher Stefan Siegel, referring to efforts to use sensors and adjustable parts to control how fluids flow around airfoils like wings. "For an airplane, when you control that flow, you better control flight - for example, enabling you to land a plane on a shorter runway."

The researchers realized they could operate a wave energy device using the same feedback control concepts they had been developing. Supported by a grant from the National Science Foundation, they developed a system that uses lift instead of drag to cause the propeller blades to move.

"Every airplane flies with lift, not with drag," says Siegel. "Compare an old style windmill with a modern one. The new style uses lift and is what made wind energy viable - and it doesn't get shredded in a storm like an old windmill. Fluid dynamics fixed the issue for windmills, and can do the same for wave energy."