Effects of Aeroelasticity on Buffet Onset of Mach 0.8 Transonic Truss-Braced Wing

This paper presents a buffet simulation of the Mach 0.8 Transonic Truss-Braced Wing (TTBW) aeroelastic model using CFD solver FUN3D. A jig twist optimization is performed to obtain a flight optimized jig twist for the flexible Mach 0.8 TTBW model. A series of Delayed Detached Eddy Simulation (DDES) aeroelastic simulations has been conducted at Mach number 0.8 and altitude 40,000 ft using a structural damping of 2% to compare the pitch break prediction and the buffet behavior for the TTBW aeroelastic model. The unsteady pressure begins to grow at angle of attack of 4.0◦, which might indicate the buffet onset, and rises one order of magnitude larger at angle of attack of 4.5◦. In contrast, the buffet onset for the TTBW 1g model appears to be at the angle of attack of about 3.5◦. The delay in the buffet onset of the aeroelastic model is due to the load relief from the aeroelastic effect.