Measurement of Aerodynamic Coefficients of Spherical Objects Using an Electro-optic Device

Aerodynamic coefficients are required to determine the trajectory of moving objects. These coefficients are typically obtained measuring the forces acting on the object using a wind tunnel. Wind tunnels are expensive and not easily available; therefore, their use is limited. This paper presents a new procedure to measure aerodynamic coefficients of spherical objects using an electro-optic device. Forces are calculated from velocity changes instead of being directly measured. The procedure is based on a method to measure the three components of the instantaneous velocity vector at known positions. The main advantages are size, cost and complexity reduction compared to wind tunnels. These advantages open the possibility of integration in production lines for quality control. A prototype has been built and tested using soccer balls.