Flutter analysis with structural uncertainty by using CFD-based aerodynamic ROM

This paper presents a novel and efficient methodology for flutter analysis with structural uncertainty in conjunction with an expedient CFD-based aerodynamic reducedorder modeling. The non-parametric structural uncertainty approach allows one rapidly investigate the effects of uncertainty towards to the dynamic system in the case when not enough information about the structural uncertainty is available. With the structural equations represented in the modal space and the baseline structural modal shapes used for all the variations of the structure, one set of aerodynamic reduced-order-models that suit for all the structural variations become feasible and thus significantly reduce the computational expense. Specifically, ARMA models for the generalized aerodynamic forces are developed by using an Euler-based CFD solver. The aeroelastic governing equations are converted into the discrete state-space form, and thereafter can be conveniently linked with the aerodynamic ROMs. The flutter speed is then determined by examining the damping coefficient of the time responses of the modal coordinates. A heavy version of the Goland wing is analyzed as a numerical example to demonstrate the present methodology.