Finite Element Analysis of a Ground Plane Wind Tunnel Roller Section

Abstract

Wind tunnels have long been used to examine the aerodynamics of various models prior to (and parallel with) actual flight testing. However, the data collected from traditional wind tunnels can be erroneous when examining models which travel close to the ground or in what is often referred to as ground effect. Because traditional wind tunnels have a fixed ground plane, the aerodynamics expressed in these wind tunnels is not completely accurate because the fixed ground plane is not a true representation of what actually occurs beneath such models as automobiles, where the ground moves beneath the vehicle. In order to accurately represent actual conditions applied to vehicles traveling close to the ground, a wind tunnel with a moving ground plane is required. West Virginia University has developed a moving ground plane wind tunnel (MGPWT) in order to replicate the actual operating conditions of such models. The MGPWT developed utilizes a conveyor belt 30 inches wide by 90 inches long which travels at speeds up to 40 feet per second in order to simulate the effects of the models moving in close proximity to the ground. It was desired that the MGPWT utilize standard conveyor rollers to drive the wind tunnel conveyor belt because this would allow for easier construction of the wind tunnel. This created a problem because most conveyor roller manufacturers do not manufacture rollers rated for the speeds necessary to perform the discussed wind tunnel testing. In order to select a standard roller which was capable of operating at the required speed, finite element analysis (FEA) was applied to existing rollers in order to determine if they were capable of operation under our specified loading conditions. This paper outlines the use of FEA in the roller selection process and provides an analysis and design criteria for such a design process.