Towards Real-Time Coupled Ship-Rotorcraft Interactional Simulations using GPU-Accelerated Lattice-Boltzmann Method

Many traditional ship-rotorcraft interactional simulation approaches, including those used for pilot training, use a one-way coupling between aerodynamics and flight dynamics. In a one-way coupled method, the standalone ship airwake is superimposed on the rotor, modifying its inflow. However, because the rotor wake does not alter the ship airwake in such a simulation, one-way coupling may not capture all relevant phenomena, such as dynamic ground and wall effects; two-way fully-coupled simulations may be needed. In this study, one- and two-way coupled realtime and near-real-time simulation models of the ship-rotorcraft problem were developed using a GPU-accelerated Lattice-Boltzmann Method (LBM) flow field solver. Comparing flow fields and rotor hub loads, the two-way coupled simulations showed good agreement with new ship-rotor experimental data from Georgia Tech. Real-time full-scale rotorcraft ship approach maneuvers of a notional UH-60A landing on the NATO Generic Destroyer were conducted using a flight controller, and the results showed significant differences in flight control inputs between one- and two-way coupling methods. On the other hand, the presence of ship motion was found to have little effect on the control inputs. The study proved the feasibility of real-time fully-coupled ship-rotorcraft flow field simulations, achieving real-time performance on a single GPU node, and it paves the way for fully-coupled LBM pilot-in-the-loop flight simulation trials.