Contributions to Ship-Airwake-Rotor Coupling Characterization Using Controlled Forcing

<p>Shipboard helicopter operations occur within a highly unsteady environment referred to as the dynamic interface (DI), encompassing the coupled effects of the ship airwake, rotor wake, flight dynamics, and pilot response. A central aspect of the DI is the aerodynamic interaction between the ship airwake and the rotor wake, which degrades handling qualities and increases pilot workload, yet the underlying mechanisms governing ship-rotor coupling remain insufficiently understood. The ship-rotor aerodynamic coupling was examined using two canonical ship geometries, the NATO-GD and SFS2, together with a controlled experimental framework, the airflow-and-blade-frequency (ABF) system, which independently varied wake momentum flux and unsteady forcing frequency. Particle image velocimetry measurements were used to characterize both isolated and coupled flow fields across a range of operating conditions. Mean-flow superposition and spectral analyses were employed to assess the validity of linear superposition in modeling the DI. In addition, a reduced-order model based on proper orthogonal decomposition decomposed the flow into time-dependent linear and nonlinear components and identified regions of constructive and destructive interference. The results showed that aerodynamic coupling produced a significant increase in turbulent kinetic energy over an extended region of the flight deck, driven by rotor-induced feedback into the ship airwake, particularly within frequency ranges associated with elevated pilot workload. For the NATO-GD configuration, the coupling was strongly nonlinear and could not be represented by linear superposition, with elevated energy levels persisting across all ABF operating conditions. The SFS2 geometry exhibited weaker coupling, with flow features more closely approximated by linear behavior. These findings demonstrated that the degree of nonlinear coupling was geometry-dependent and must be accounted for in aerodynamic models of the DI, thereby providing a physics-based foundation for improving shipboard flight simulators through more realistic representations of the unsteady disturbance environment encountered in the DI.</p>

Name thesis:degree_name

Doctor of Philosophy in Aerospace Engineering

Level thesis:degree_level

Dissertation - Open Access

Discipline thesis:degree_discipline

Aerospace Engineering

Year

2026

Author dc:creator

• Mazzilli, Guillermo

• ship airwake
• rotor aerodynamics
• wind tunnel testing
• dynamic interface
• Aerodynamics and Fluid Mechanics
• Aerospace Engineering
• Engineering

Repository record dc:identifier

https://commons.erau.edu/edt/978

OAI identifier oai:identifier

oai:commons.erau.edu:edt-2023