Oscillating Turntable for the Measurement of Unsteady Aerodynamic Phenomena

A new forced oscillation system has been installed and tested at NASA Langley Research Centerʹs Transonic Dynamics Tunnel. The system is known as the Oscillating Turntable (OTT) and has been designed for the purpose of oscillating, large semispan models in pitch at frequencies up to 40 Hz to acquire high-quality unsteady pressure and loads data. Precisely controlled motions of a wind-tunnel model on the OTT can yield unsteady aerodynamic phenomena associated with flutter, limit-cycle oscillations, shock dynamics, and nonlinear aerodynamic effects on many vehicle configurations. This paper will discuss the general design and components of the OTT and will present data from performance testing and from research tests on two rigid semispan wind-tunnel models. The research tests were designed to challenge the OTT over a wide range of operating conditions while acquiring unsteady pressure data on a small rectangular supercritical wing and a large supersonic transport wing. These results will be presented to illustrate the performance capabilities, consistency of oscillations, and usefulness of the OTT as a research tool.