Engineering Applications of Computational Fluid Mechanics (Jan 2020)
Numerical investigation of the unsteady coupling airflow impact of a full-scale warship with a helicopter during shipboard landing
Abstract
In this paper, a comprehensive computational modeling study of the unsteady aerodynamic environment around a warship with a helicopter is performed. An experimental validation exercise is also conducted, comparing computational fluid dynamics (CFD) results of the airwake calculated for a reduced-scale model of the isolated Landing Helicopter Assault (LHA) model with high-quality particle image velocimetry experimental data provided by the NASA AMES Research Center. Comparisons of the results generally obtain agreement, indicating that the CFD numerical method is able to resolve the large-scale turbulent airflow. Building on this, a numerical simulation of a real Robin helicopter, immersed in the unsteady airwakes of a full-scale Amphibious Assault Ship (AAS), is performed. The aerodynamic simulation of the influence on the coupled airflow of warship–helicopter is explored and compared with that of the solitary ship airflow field and the superposition airwakes, where the vortex patterns and pressure on the ship surface, as well as the velocity distribution, are circumvented. As a further step, dynamic landing analysis of the airflow field for a shipborne helicopter is implemented at an important location through the landing path for headwind. The aerodynamic characteristics of a helicopter during a flight deck landing are also explored for the unsteady ship airwakes impacting on rotor force during shipboard landings. In addition, different shipboard landing paths of the helicopter are comparatively investigated for obtaining an optimal landing path decision. The present study demonstrates an effective aerodynamic analysis and robust numerical approach, which creates a solid foundation supporting further alternative evaluations of ship airflow fields.
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