Aerodynamic load evaluation on a highly flexible wing by Lagrangian Particle Tracking

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Abstract

The technical advancements achieved during the last decade have permitted the implementation of low-fidelity numerical methods to analyze simplified aeroelastic problems. However, the available computational power is still incapable of dealing with more realistic events involving complex structural dynamics and flow regimes. For this reason, experimental wind tunnel campaigns are still required to characterize relevant fluid-structure interaction events and to assist in the development of more accurate computational models. Nevertheless, conventional measurement systems present several constraints that limit the complete description of the phenomena being analyzed. This thesis is part of the research effort to define alternatives capable of providing full-field and simultaneous information of both flow and structural quantities in a non-intrusive way.

A wind tunnel experimental campaign has been developed in the Open Jet Facility to evaluate the ability of Lagrangian Particle Tracking (LPT) to characterize aerodynamic loads acting on large-scale flexible bodies. Three different load reconstruction approaches have been considered for this purpose: integral momentum conservation equation in its classical formulation, integral momentum conservation equation with an alternative formulation based on vorticity, and Kutta-Joukowski theorem. The accuracy and precision of each of the forenamed procedures have been assessed in both steady and unsteady inflow conditions taking force balance measurements as a reference.

The results of this thesis have proven the capabilities of LPT to determine the aerodynamic loads in aeroelastic wind tunnel investigations with acceptable accuracy and precision. Finally, it has also been demonstrated that the range of information provided by these techniques is superior to that achievable with conventional measurement devices, which improves the overall characterization of the fluid-structure interaction phenomena.