Mid-Fidelity Ship--Rotor Interactional Aerodynamic Simulations Using GPU-Accelerated Lattice-Boltzmann Method With a New Actuator Line Method Rotor Model

A new Actuator Line Method (ALM) rotor model was developed and coupled to a GPU-accelerated Lattice-Boltzmann method (LBM) computational fluid dynamics (CFD) solver for analysis of rotorcraft--ship deck aerodynamic interactions. Upon validation and convergence studies for an isolated rotor based upon the Hover Acoustic Baseline Rotor (HVAB) experimental dataset, the new ALM was compared to an existing Actuator Disk Model (ADM) and validated against 1:100 scale NATO Generic Destroyer (NATO-GD) ship--rotor interactional experimental data. While the existing ADM approaches successfully captured general interactional aerodynamic phenomena well, the ALM proves capable of higher-fidelity simulations through its ability to resolve individual blade effects in the flow fields. This is proven through more accurate predictions of time-averaged and unsteady rotor loads throughout a grid survey of varying rotor locations on and near the flight deck, as well as time-averaged flow field analysis. Although the ALM has a higher computational cost than the ADM, when implemented in the LBM simulations, it bridges the gap between lower-fidelity real-time models and high-fidelity CFD methods that are often computationally prohibitive.