Practical Considerations using Weighted-Acceleration Compensation Techniques for Dynamic Force Measurements in Wind Tunnels

Abstract

Most wind tunnel force measurement systems are designed and calibrated for high-accuracy static measurements, but may have limited ability to sense dynamic forces and moments. As a means to improve the measurement bandwidth of dynamic forces, researchers have proposed using a weighted-acceleration technique, which uses accelerometer data to compensate and correct for system dynamics. The sum of weighted-accelerations method is attractive as the acceleration data applies a correction to the traditional static measurements. The focus of this paper is on practical aspects of implementing a weighted-acceleration technique in an experimental arrangement. A formulation of the weighted-acceleration methodology is validated on a reduced-order model and demonstrated on a tabletop experiment that serves as a proxy to a wind tunnel force measurement system. As part of this system, a two component normal force and pitching moment balance was designed and fabricated. A static and dynamic calibration of the system was performed, and the weighted-acceleration technique was used to reconstruct impact forces acting on the system. Practical considerations of the experimental design that improve the success of the methodology are discussed.