טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAvraham Zaide
SubjectCFD-Based Time-Domain Aeroelastic Gust-Response Model
DepartmentDepartment of Aerospace Engineering
Supervisor Professor Raveh Daniella
Full Thesis textFull thesis text - English Version


Abstract

Aeroelastic gust-response analysis requires an aerodynamic model of the unsteady forces that develop on an aircraft or airfoil as it travels through atmospheric gust. In such analysis the local angle of attack varies both with time and location, on the wing and on the local airfoil. Computational Fluid Dynamics (CFD) based simulations, along with parametric and non-parametric Reduced-Order Models (ROM) for such responses were computed in this research. A CFD code was enhanced to simulate responses of several airfoils and a full-scale wing, to arbitrary shaped gust inputs. Time-domain Auto-Regressive-Moving-Average (ARMA) models were identified based on CFD responses to random gust excitations, using system identification methods. Responses to discrete gusts of various shapes, amplitudes and gradient lengths were computed via the ROMs and compared to responses simulated directly by the CFD code. The ROMs predict the lift and pitching moment histories accurately throughout the subsonic and transonic regimes. They offer significant savings in computational resources compared to the full CFD simulation, since only one CFD run is required for ROM identification, from which responses to arbitrary shaped gusts can be rapidly estimated. The combination of ROM and full CFD simulation offers a computationally efficient tool-set of various-fidelity time-domain models for gust responses. The ROM can be used for rapid tuned-gust analyses, and the critical cases can be simulated with a full CFD run, providing pressure distribution for airframe structural design.