Chaos Analysis of a Fuel-Slosh Coupled Aircraft System

This study investigates nonlinear and chaotic dynamics induced by fuel sloshing in a partially filled aircraft tank. The system is modeled as a rigid aircraft pitch degree of freedom coupled with a nonlinear slosh pendulum, representing the dominant liquid motion. Numerical simulations are used to analyze the system response through time series and phase portraits, revealing complex dynamical behavior. Chaotic dynamics are quantitatively confirmed using Lyapunov exponents and their parametric variation. In addition, bifurcation analyses are performed with respect to key system parameters, illustrating transitions from periodic to chaotic motion. The results highlight the significant impact of fuel slosh on aircraft pitch dynamics and emphasize the importance of accounting for nonlinear fluid–structure interactions in stability analysis and control-oriented modeling.