Redesign of an Adjustable Slope Moving Ground Plane Wind Tunnel

Abstract

Ground effect is an aerodynamic phenomenon that occurs when moving bodies come in close proximity to the ground. A “cushion” of air is created underneath the moving body which provides additional lift by increasing the local pressure under the body surface. To experimentally test ground effect vehicles, a unique wind tunnel is currently being redesigned and constructed at West Virginia University. This wind tunnel incorporates a rotating belt as the ground plane and a centrifugal fan that generates the air flow through the test section in the same direction as the belt’s rotation. The combination of a rotating belt and airflow is used to mimic ground effect in that it is representative of a body moving through still air in close proximity to the ground. The test section and fan assembly sit on a platform that is connected to a movable base frame. The base and testing platform connect through a pivot point that is capable of being raised upward to a maximum angle of fifty degrees to account for gravitational vector alignment between modeled and real world conditions. When the platform is raised and the belt is spinning, the structure is less stable and has the potential to create errors in force readings due to these oscillations, as well as the potential to tip in extreme wind conditions. Thus, the evaluation of the original design and the subsequent redesign are addressed in this research effort. To stabilize the wind tunnel, additional structural elements have been added downstream of the test section. Two telescoping poles were added to the end of the platform that will connect onto outriggers attached to the base structure. These poles and outriggers will form an A-shape support system when the platform is raised to any degree between zero and fifty. The width of the outriggers was calculated and then modeled in conjunction with the existing base structure. The final design is presented in this paper.