An Indian engineer, Ramesh K Agarwal has developed a technique that helps in improving the gas mileage by reducing the drag of vehicles. Agarwal, who is the William Palm Professor of Engineering at Washington University in St. Louis, has shown through his studies that the Active Flow Control (AFC) technology can be used to reduce the drag of airplanes, cars, trucks and other vehicles.
Drag is an aerodynamic force that is the result of resistance a body encounters when it moves in a liquid or a gaseous medium such as air. When the drag of a vehicle is reduced, lesser fuel is required to overcome the fluid resistance encountered by the vehicle in motion.
The AFC technology is applied by deploying actuators on the vehicles. These Actuators then modify the airflow in a manner that reduces the overall resistance of the vehicle. This in turn reduces the amount of fuel required to propel the vehicle. According to the Lawrence Livermore National Laboratory, overcoming aero-drag represents more than 50% of vehicles energy expenditure at highway speeds.
Agarwal reduced the transonic drag on an airplane wing by 12%- 15% by adding 20-30 three-ounce actuators on them. Similarly, he reduced the drag of cars and trucks by 15%-18% by placing actuators on the back surfaces of the vehicles. The AFC technology can, hence, be instrumental in the conservation of fuel as well as reduction in the emission of greenhouse gasses.
The technology is being investigated and researched by a number of airplane and automobile companies across the world, though it has not yet been deployed on any commercially available vehicle.