Development of the Snapshot Method for Six Degree-of-Freedom Flight Dynamics Simulation of a High Aspect Ratio Wing Aircraft

The purpose of this paper is to develop a six degree-of-freedom flight simulation while considering the flexibility of an aircraft with high aspect ratio wings using by new quasi-steady temporal coupling scheme named ‘snapshot method’. The simulation was based on the quasi-steady temporal coupling scheme for the flow field, elastic structure, and rigid body motion problem. A full three-dimensional finite-element model of unmanned aerial vehicles was used. The object aircraft has main wings with an aspect ratio over 20 and a flight for long endurance in high altitude. To consider the flexibility of these aircraft, the present snapshot method was developed that combines ‘aerodynamic—structural dynamics—flight dynamics’ to analyze dynamic response. By applying this method, MATLAB/SIMULINK, which analyzes the rigid body motion, and MSC FlightLoads, which is responsible for aeroelastic trim analysis, was tightly linked into the present simulation framework. Using the present simulation, aircraft response under various maneuver conditions was simulated. First, the trim analysis for the level cruise was performed. Trim parameters, stability derivative coefficients, and the moment of inertia were also determined. Based on these results, the flight dynamics of the aircraft was simulated according to the operation of the rudder and the aileron control surface. The effect of the rigid and flexible body assumptions was also confirmed. In addition, these results were compared with other existing simulation results based on the multibody dynamics under the same conditions. To predict the response of the aircraft under the gust, the simulation was performed by applying the two-dimensional 1-cosine discrete gust profile. The important aspects, such as numerical prediction methods during stages of the highly flexible aircraft design process for a countermeasure to various challenging problems, were shown.