Flutter Testing Methodology for Swirl Distortion Generators

StreamVane devices are swirl distortion generators consisting of complex vane packs used to recreate secondary flow distortions. To ensure the structural integrity of these complex vane packs, further research was needed to study flutter of these devices and complex vane packs in general. The objective of this research was to develop a methodology for studying flutter in these devices and take an initial look at possible mechanisms that could cause it. High speed cameras were used to observe the onset of flutter and record the trailing edge motion. A method was then developed using this calibrated high speed video to obtain accurate displacements along the trailing edge of the vanes. For this investigation, two StreamVanes were designed outside of standard design guidelines to increase the likelihood they would flutter. These StreamVanes consisted of a larger, complex vane pack and a more simple vane pack taken from one section of that larger one. These devices were found to flutter in a similar Mach number range indicating flutter more localized geometric features could be an issue and not just the entire complex structure. Steady CFD was then performed to examine the flow structure and local Mach numbers through the passages. This identified some possible aerodynamic issues such as separation and transonic flow that could lead to unsteadiness and other potential problems. These results provide some insight into the flutter behavior of these complex vane packs and will serve as a baseline for future research into the structural integrity of these devices.