Higher-Order Transonic Flutter Solutions

This paper presents a method to couple a finite-element based compressible Euler solver to a finite element structural solver for flutter analysis using a conventional eigensolution approach, such as U−g method that is used in this work. The Euler equations are linearized about a steady-state solution and converted to frequency-domain for small-perturbations for direct evaluation of the unsteady generalized aerodynamic forces that are directly used in a flutter solution procedure. The eigensolution approach allows for the identification of multiple flutter modes at a reduced computational cost, making it computationally attractive in comparison with fluid-structure interaction techniques that use time-integration to identify the critical flutter velocity. Numerical results are presented to benchmark the solution procedure and the order-of-accuracy is obtained through computational study of a two-dimensional panel flutter problem. The results show that for the same number of degrees-of-freedom the high-order solution more accurately predicts the flutter velocity.

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