Abstract: A rapid deforming technique is developed to generate three-dimensional multi-block dynamic attached meshes. A second-order accuracy Runge-Kutta time stepping is used to solve structural equations of motion and a dual-time method is applied to the finite-volume element method for unsteady Euler equations to calculate the aerodynamic forces, in which the physical time step is synchronous with the structural equations of motion. In a real-time step, a five-stage Runge-Kutta time stepping is applied to the fictitious steady iterations. Because of mass dissimilarity exiting in flutter calculations for a compressible flow, a method of variable mass and variable stiffness is developed to calculate the fluttering dynamic pressure at the point of mass similarity, and the flutter characteristics are then obtained in accordance with similarity rule. For completeness, the transonic flutter characteristic results, calculated using the method, are presented for a simplified fighter model.

Key words: transonic flow, unsteady flow, Euler equation, flutter