Body freedom flutter of a flexible blended wing body like plate - an experimental study

Aeroelastic modeling, analysis, and wind tunnel flutter test was conducted to investigate the body freedom flutter problem of a blended wing body (BWB) like flexible plate. The plate is made by aluminum with constant thickness of 0.2mm which resembles the shape of a high aspect-ratio configuration. Two types of suspension, i.e. nylon cord (D = 0.23mm) and bungee cord (D = 0.8mm), were implemented to study the influence of support stiffness on the body freedom flutter characteristics of the BWB like plate model. A gyro, attached on the upper surface of the plate model, was employed as sensor and connected to the data acquisition Arduino board by a flexible electric wire for data acquisition. It is found that both suspension types and the flexibility of the gyro’s electric wire contribute to the support stiffness. While with the current suspension setup neither the free-free pitching mode, due to the added pitching stiffness coming from the flexible wire, not the free-free plunging mode, due to the suspension stiffness, could be accomplished, the flutter results predicted by an updated model accounting for the support stiffness, could produce quite satisfactory agreement with the test results. Lesson learned suggests that neither elastic nor rigid suspension can fully satisfy the body freedom flutter test requirement, and free-flying model setup is recommended for future wind tunnel test.