Characterization of Stability and Control Derivatives Through Water-Tunnel Testing

摘要

The primary purpose of this invited paper is to present a brief description of a key experimental capability within Boeing Research and Technology (BR&T) for characterizing aircraft static and dynamic control derivatives, that being the BR&T water-tunnel test facility, located in Huntington Beach, California. While water-tunnels have traditionally been used for flow-visualization, the BR&T water-tunnel offers the additional capability of measuring static and dynamic derivatives of flight vehicles via a six degrees-of-freedom, submersible, force and moment balance using a modified rig, at a significantly lower costs when compared to other test facilities. This additional capability, which was the result of an upgrade project that was originally initiated in 2005, has facilitated the simultaneous measurement of loads with flow field observations, so that the measured forces and moments can be correlated directly with the recorded flow field images, thus rendering the facility ideal for fundamental research projects. One such project recently executed at the facility was the NASA Vehicle System Safety Technologies (VSST) research program, which was successfully concluded in September 2017, and for which the focus was on the modeling of flight dynamics of transport aircraft approaching and during loss-of-control events, such as stall. The relative insensitivity to Reynolds Number of the largely unsteady flow fields that dominate such events, the model's low rotation rates that are inherent of dynamic testing in water-tunnels, and the tunnel's low operating costs were some of the factors that favored the BR&T water-tunnel for this NASA research. In addition to describing the host test facility and its validation tests, this paper also offers a glimpse into the results of the aforementioned NASA project.