Improved Models for Prediction of Locally Intense Aeroacoustic Loads and Vibration Environments

ATA Engineering, Inc. proposes an STTR program to develop innovative tools and methods that will significantly improve the accuracy of random vibration response predictions for aerospace structures under critical inhomogeneous aeroacoustic loads. This will allow more accurate predictions of structural responses to be made, potentially reducing vehicle weight and cost and improving the reliability of these structures. Empirical wind tunnel test data will be used as a basis to develop novel methods to characterize the surface fluctuating pressures encountered by launch vehicles during ascent, and then to accurately predict the random vibration environment caused by these loads. In Phase II, we will perform a wind tunnel test campaign at the University of Mississippi to measure both the surface fluctuating pressure and the resulting vibration in a flexible panel positioned on an expansion corner. The data from these tests will be used to develop more accurate models to predict the auto- and cross-spectra of surface fluctuating pressures during ascent, followed by the development of coupling models to predict the resulting spacecraft structural vibrations. A critical improvement over current methods will be the inclusion of a statistical basis which will enable prediction of both mean and maximum expected environments. The experimental data in Phase II can also be used as a source of validation for unsteady coupled fluid-structural dynamics simulations.