Effects of Plunging Motion on Unsteady Aerodynamic Behavior of an Aircraft Model in Compressible Flow

Aspects of pitching and plunging motions on unsteady aerodynamic behavior of an aircraft model were studied. Extensive wind tunnel tests were performed on a standard dynamics model, SDM, oscillating in both pitch and plunge modes. Up to now, there has been little or no result on the plunging behavior of an aircraft or missile as a whole and the present experiments can be considered as one of the first attempts to study the compressible flow field over a model undergoing both pitching and plunging motions. The experiments involved measuring normal force and pitching moment of the model at Mach numbers of 0.4, 0.6 and 1.5 and oscillation frequencies of 1.25, 2.77 and 6.00 Hz. The longitudinal dynamic derivatives were then calculated from the measured data. The pitching results have been compared with the available data on the same model and good agreement has been achieved. However no plunging data on the same or a similar model was available in the literature to be compared with the present findings.