Aeroelastic analysis of a low aspect ratio wing 13; 13;

Analytical predictions of aeroelastic behavior like flutter and divergence of a typical wing configuration are presented in this paper. To facilitate the calculation of steady or unsteady airloads, the modal data of the wing configuration in the form of a limited number of low frequency mode shapes and their associated generalized masses and stiffnesses are generated using CSA /NASTRAN. Unsteady airloads required to perform flutter analysis are evaluated for a set of natural modes using piston theory. The flutter model formulated combining the structural and aerodynamic models is solved using KE method available in CSA/NASTRAN. Critical flutter Mach number and flutter frequencies are calculated from the condition that the damping of the whole system should be zero. To calculate steady air load in the supersonic regime, the normal mode shapes are expressed in the form of polynomials. Then the divergence equation, formulated by combining the steady airload and stiffness matrix, is solved as an eigenvalue problem to obtain the divergence Mach number for the wing. (Author

Feasibility study of a spring support system for buffet models and a mini shaker for model excitation

To simulate free flight condition, an aeroelastic model has to be suspended on springs in the wind tunnel. This report describes the feasibility study of a leaf spring and a coil spring system for this purpose. Also the successful testing of a mini shaker for its capacity to excite the model in the tunnel for aeroelasuic damping measurement is reported