On the Mechanical Design of the Rolling Road Addition to the CSUF Wind Tunnel

For ground effect aerodynamic studies in wind tunnels, boundary layer growth over the floor of the test section is a large concern. Many different techniques have been used to remove this boundary layer, of which creating a moving ground plane is considered the best option. By creating a moving floor in the test section, the ground plane speed can be set to that of the free stream air speed, thus removing the boundary layer or at the very least mitigating the boundary layer growth. Several studies detail the aerodynamic design concerns for such devices, but little information exists on the mechanical design concerns. This work reviews lessons learned during a design study of a rolling road for the wind tunnel at California State University, Fullerton (CSUF) mainly focusing on the motor specification and cooling system design. First, an overview of the major systems that comprise a rolling road apparatus are given. Then, initial constraints and free-body diagrams are presented detailing the forces experienced by the rolling road. From these free-body diagrams, analytical equations are presented which estimate the rolling road motor power and torque requirements as well as cooling system requirements. A design study is conducted to investigate variable sensitivities and the previously derived equations are used to start initial design concepts for the CSUF rolling road. Potential areas for improvement are identified and future development work is discussed.