Fluid-structure interaction analysis in external flows using Linearized Euler solver

2022-8
Ardıç, Ata Tankut
Flutter is an aeroelastic instability that requires numerous fluid-structure interaction (FSI) analyses during the design process of an aircraft. Even with technology of today, numerical solution of FSI problems is a challenge as these of problems require a high amount of computational power. Most of the computational cost stems from the computational fluid dynamics analysis (CFD) part of the computation, and time-dependent nature of the problem. Harmonic methods, which are very cost-efficient compared to unsteady solvers, can be utilized to solve FSI problems by assuming the solution is time-periodic. In this thesis, the linearized Euler methodology, one of the harmonic methods, is used to detect the flutter speed of aircraft wings. For FSI capabilities and external flow applications, oscillating wall and characteristic far-field boundary conditions are implemented. NACA0012 airfoil with prescribed pitching and plunging motion cases are analyzed to verify accuracy of the solver. All test cases were compared against and verified with unsteady Euler solutions. Additionally, the moment damping coefficient of the basic-finner missile geometry was estimated using a prescribed pitching motion and compared to flight test data. The outcome displayed an excellent match, which confirms proficiency of the solver with 3D flows. After the validation studies, a 2D coupled structural solver algorithm was proposed to detect flutter speed. The algorithm benefits from the computational efficiency of linearized methods. Furthermore, aeroelastic analysis of the AGARD 445.6 wing was performed using its first mode shape in preparation for detecting flutter speed of 3D wings in the future.

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Citation Formats
A. T. Ardıç, “Fluid-structure interaction analysis in external flows using Linearized Euler solver,” M.S. - Master of Science, Middle East Technical University, 2022.