Helicopter Shipboard Landing Simulation Including Wind, Deck Motion and Dynamic Ground Effect

A first principles physics-based simulation framework that accounts for wind-over-deck (WOD) and ground effects during approach and landing of a helicopter on a ship deck is developed. The WOD velocities are obtained from unsteady detached-eddy simulation of the flow over a simple frigate shape version 2 ship. The HeliUM2 flight dynamics code was modified to include WOD, static and dynamic ground effects, and landing gear models. A dynamic ground effect model that combines a finite-state wake model with a ground source distribution was also incorporated. Simulations are carried out to determine the combined effect of WOD and deck motion. Representative ship motion data are extracted from the Systematic Characterization of the Naval Environment database. A simple linear-quadratic-regulator-based flight control system is used to follow a prescribed trajectory during approach and landing. High-frequency oscillations are induced by the WOD. The entire helicopter has to be modeled to capture the complete WOD effect. In-ground-effect simulations show up to 10% reduction in rotor power consumption as well as good agreement with experimental data for a stationary deck. Deck heaving motion produces an additional change in rotor power consumption relative to the static ground effect, highlighting the importance of modeling the dynamic ground effect. The controller maintains the desired approach trajectory; and successful landing is demonstrated on level, inclined, and moving decks in the combined presence of WOD and ground effects.