The modelling of aircraft wakes is of interest for a variety of applications including air-to-air refuelling and formation flight, both of which are operational practises that can result in fuel savings. However, aircraft flying in close proximity often experience disruptions during flight due to wake turbulence, downwash, and aerodynamic coupling between aircraft. In order to predict the effect of a tanker aircraft's wake on the flight dynamics of a refuelling aircraft, a coupled vortex lattice method was developed and combined with sensitivity analysis that used an adjoint-based method to quickly predict the change in pitching moment caused by changes in the relative vertical position between the two aircraft. The results from this analysis were compared to existing computational data. Results showed good agreement with trends demonstrated by the existing data in terms of the effect of the tanker aircraft on the C_L and C_m of the refuelling aircraft. Differences between models in terms of the value of the tanker's effect on the refuelling aircraft were noted. It was thought that these were differences were caused by dissimilarities in the tanker models used. The adjoint-based sensitivities were shown to be accurate compared to a finite-difference based approach, but were calculated approximately five times faster. A survey of dC_m/dz at various points behind a Hercules tanker was presented.
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