Some Remarks on Buffeting.

Buffeting is defined as the structural response to the aerodynamic excitation produced by separated flows. The aerodynamic excitation produced by bubbles, vortices and transonic flows is discussed. Different buffeting criteria for the wings of fighter and transport aircraft are developed. Methods of predicting the onset and severity of buffeting are reviewed. Some typical examples are discussed, in which improvements in wing buffeting are compared with changes in mean force measurements. The first buffeting measurements on ordinary models in a cryogenic wind tunnel are analysed. The measurements confirm that cryogenic tunnels can separate Reynolds number and aeroelastic effects. The frequency parameter must be correct on the model if the aerodynamic excitation does not have a flat spectrum, as at vortex breakdown on a slender wing. The violet periodic flows at transonic speeds recently observed on thick biconvex aerofoils are briefly reviewed and compared with solutions of the full Navier-Stokes equations. Author