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In this work, the Hydra Technologies Unmanned Aerial System (UAS) wing was simulated in several flight conditions. The simulations were carried out with the FLUENT Computational Fluid Dynamics code in 2D, and the grid was drawn with ICEM. Simulations were conducted using the turbulent models Spalart-Allmaras, SST k-ω and transition SST k-ω. The calculated results were compared with Xfoil. This comparative study allowed increasing the accuracy of the results as for the aerodynamic parameters of the wing CL, CD, CM and CP. The parallel objective was to determine the transition point. All the turbulent models were able to accurately simulate the correct behavior of the CP but transition SST k-ω appeared to be the only one able to find the transition point. In this study, we simulate, in 2D, a specific section of the wing located at the wing tip.

An airplane model is usually obtained from preliminary wind tunnel experiments and CFD analysis. These models are then tuned from flight test measurements using system identification, and are used for airplane stability assessment and control design. However, sometimes no or little preliminary data and documentation are available and flight test identification is the main mean to obtain the model needed for control system design. If so, the purpose of this paper is to identify the grey-box model of an airplane without initial data using a combination of the least square and output error estimation methods. A grey-box model identification is preferred because it gives aerodynamic parameter estimations of the airplane. Before flight test data are available, this method was applied to the Cessna Citation X business airplane's high fidelity simulations and carried out with human-in-the-loop on a professional level D flight dynamics simulator designed and manufactured by CAE Inc.