Air-to-air intercept flight requires vehicles to maintain superior maneuverability and agility to capture their target at supersonic speeds. Aggressive maneuvers create complex flows around the vehicle that lead to very high loads and interaction between the aerodynamics, structural dynamics and flight dynamics. These interactions become significant for flexible vehicles with larger deformations such as the very slender structures that may be used for air-to-air missions. A representative vehicle model has been developed based on reduced order and fundamental tools to enable the study of the aeroelastic response of a maneuvering vehicle. This paper presents the development of the vehicle model and the computational framework to analyze the aeroelastic response of the maneuvering vehicle in free flight. The vehicle response to control inputs for various values of vehicle bending stiffness and distribution is presented to investigate the variation of performance with vehicle flexibility. The results show that the vehicle loading, maneuverability, and agility are all dependent on the vehicle structural configuration. Therefore, accurate analyses of future designs are dependent on vehicle modeling as flexible structures. Understanding the aeroelastic response of a flexible munition could lead to vehicle stiffness becoming an additional design parameter to improve maneuverability and agility.

Future transportation aircraft requirements focused on energy efficiency and environmental impact are leading to design concepts with very high-aspect-ratio wings. These slender wings aim to maximize efficiency by reducing drag and lowering structural weight, but can lead to larger structural deformations under aerodynamic loading and tighter coupling between the aeroelastic response and flight dynamics of the vehicle. Current engineering practice is to use wind tunnel testing to predict the stability and performance characteristics of the vehicle. However, the flutter boundary and mode maybe very different for a flexible vehicle in free flight compared to the cantilevered wing model alone. The coupled aeroelastic and flight dynamic response of an aircraft concept with a flexible high-aspect-ratio wing is investigated to better understand the nonlinear aeroelastic implications of these future design trends. This paper reports the impact of the aeroelastic and rigid body interaction on the free flight flutter boundary and vehicle response. i Autoregressive model time index i Point mass index k Step response time index, 1...n x, y, z Body coordinate frame 1, 2, 3 Beam axis

This paper presents high-fidelity solutions of the fluid-structure-jet interaction problem for slender high-speed vehicles along with two jet interaction modeling methods, one semiempirical and one CFD-based, to approximate the high-fidelity solution. The high-fidelity solutions of a representative high-speed vehicle with jet interaction and structural deformation show that the resultant loads are affected by the deformation. The semi-empirical jet interaction model is developed using previous work in the literature and approximates the main features of the jet interaction solution when compared to numerical and experimental results. The CFD-based jet interaction model is developed by using data-fusion of a previously developed aerodynamic loads surrogate, the semi-empirical jet interaction model, and CFD solutions of the jet interaction. This data-fusion model approximates the surface pressure of a representative high-speed vehicle with varying flow, structure, and jet parameters and can be used within a flight simulation framework. Overall, the work demonstrates a need to model the fluid-structure-jet interaction of high-speed vehicles and modeling methods that may be used to approximate the full solution.

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