Wind tunnels are facilities in which the wind is produced by fans or by compressed air to study and measure the action of the air flow around a solid. There are two basic types of wind tunnels: the closed-circuit and the open-circuit. Open-circuits draw air from the ambient environment and exhaust it back to the ambient after exiting the fan, while in closed-circuit, the air repeatedly circulates through the tunnel. The closed-circuit design delivers improved efficiency and generates less noise, but it is more expensive and more difficult to manufacture. Wind tunnels are typically used in...