| The National Transonic Facility (NTF), at NASA Langley Research Center, is a cryogenic wind tunnel that provides unique high Reynolds number capability. There have been major problems with unexpected model vibrations in the NTF. Excessive model vibrations, during a steady state test, are undesirable because they interfere with the achievement of the test objectives. One possibility to suppress these vibrations is model system de-tuning. A wind tunnel model system simulator has been developed and validated to assess the viability of the model system de-tuning concept. This document provides the equations of motion, a discretization approach, the simulator implementation details, validation experiments, and parametric sensitivity studies. Significant findings include the sensitivity of the model system dynamic response to the elastic boundary representation, and the requirement for advanced model support development. Successful application of model system de-tuning was found to be tied to the stage in which dynamic design criteria are considered. |
