Buffeting Prediction for Transport Aircraft Applications Based on Unsteady Pressure Measurements

At ONERA a buffet onset prediction method based on computation of aircraft dynamic responses from the measurement of the unsteady pressure field on a model with scaled static deformation and geometry is under development. To build up such a method several experimental tests were performed on both RA16SC1 airfoil and rectangular wing to analyze in details unsteady separated flows. The existence of organized separated flow fluctuations at transonic speeds was observed. But this type of flow does not seem to be relevant at buffet onset for transport aircraft. Dynamic buffet responses have also been calculated on a 1/38 scale wing model from more complete unsteady pressure measurements. Reasonable agreement was obtained with experimental results at least for transonic speeds.