Adjustable Slope, Moving Ground Plane Wind Tunnel

摘要

Ground effect is a phenomenon where the airflow around a moving body is affected when in close proximity to the ground. This is caused by the compression of air between a vehicle and the ground, which displaces airflow above the ground plane. The altered aerodynamic forces created by ground effect can aid during certain flight operations by increasing lift or act as hindrance by causing pitch instability if not taken into account. An example of the usefulness of ground effect is the upward thrust exhibited on a plane during landing. Pilots account for this air movement to prevent a jump-like event that is particularly noticeable in smaller, general aviation aircraft. Since all the surfaces on the earth are not level nor exhibit the same conditions, a wind tunnel with a movable ground plane, which can be positioned throughout a range of ground slope angles, was designed and developed.The varying slope movable ground plane wind tunnel is comprised of an elongated platform balanced on a rectangular base that holds both a test section and its adjoining fan. The test section floor is comprised of a rotating belt that mimics the influence of the ground on a vehicle moving over the ground plane and is used in conjunction with a fan that provides the air movement that represents the relative velocity of the model's environment. The base itself is designed to set at a point in which the platform, in its horizontal position, would be balanced. In addition, the base is designed to position to various angles of ground slope and be able to adjust to any angle within the prescribed range of -5 degrees and 50 degrees. With the exception of the fan, all components of the tunnel were designed and constructed in this research effort.