Solving the Ship-Rotorcraft Dynamic Interface Problem Using Lattice-Boltzmann Aerodynamics Two-Way Coupled with Blade Element Based Flight Dynamics

Abstract

A dynamic interface model based on a Lattice-Boltzmann fluid solver two-way coupled with flight dynamics is introduced. The model is neither limited to helicopters, nor by the number of rotors or their size. Although applied to a landing approach of a MBB Bo105 helicopter on a SFS2 ship in the current work, the introduced dynamic interface model is applicable to any situation with interactions between random solid objects, their wakes, and rotor wakes. The model uses a pre-computed airwake solution of the ship, which can be computed by any CFD solver or method. In this work, the SFS2 airwake was simulated for three different resolutions using the sameLattice-Boltzmann solver that was used for the dynamic interface model. The computed airwake was validated using PIV and higher-fidelity URANS data. Furthermore, an analysis of the frequency spectra of the velocity fluctuations in the ship airwake was related to frequency ranges that are of particular importance to the pilot. Using this ship airwake, the dynamic interface model was convergent with a resolution that was real-time computable for the simulated approach. The effects of the two-way aerodynamic interactions of the ship deck, walls and the ship airwake with the rotor wake on the rotor airloads was captured. In its current model development stage, data import from hard disk drive was identified as bottleneck for a piloted evaluation in flight simulators.