People are building large wind farms around the world as a cleaner way to generate electricity, but operators are still searching for the most cost-effective and efficient way to arrange the massive turbines that turn moving air into power. To help steer wind farm owners in the right direction, Charles Meneveau, a Johns Hopkins fluid mechanics and turbulence expert, working with a colleague in Belgium, has devised a new formula through which the optimal spacing for a large array of turbines can be obtained.