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Date of Award
Doctor of Philosophy (PhD)
Dynamic stall is a complex aerodynamic phenomenon occurring in helicopter rotors, limiting the flight envelope and causing control linkage damage and instabilities. The Peters-Modarres semi-empirical dynamic stall model is extended to simulate pitching moment and drag in unsteady freestream and yawed flow, including the effects of secondary stall. The aerodynamics are implemented as a state-space model, suitable for time-marching or aeroelastic analyses. With small modifications to the original stall model, secondary stall effects and unsteady freestream can be simulated without adding additional states. An optimization routine determines sets of parameters that minimize the error between the modeled solution and experimental data. The stall model is validated against five wind tunnel tests with a range of aerodynamic conditions. The results show good qualitative correlation with each test case, improving on the pitching moment and drag results of previously found by Ahaus.
David A. Peters
Available for download on Friday, January 24, 2020