Mid-Fidelity Lattice-Boltzmann Simulations Of Proprotor-Wing Aerodynamic Interactions

Abstract

This study investigates the capability of quick turnaround mid-fidelity Lattice-Boltzmann Method (LBM) simulations to resolve complex aerodynamic interactions between proprotors and wings in tiltrotor configurations. A GPU-accelerated LBM solver was coupled with an actuator line model to capture proprotor-induced effects across a range of proprotor tilt angles. An explicit power-law wall model was developed and integrated into the LBM framework to provide near-wall treatment based on velocity profile assumptions. This approach was evaluated in parallel with a no-slip immersed boundary formulation, which does not constitute a wall model but only enforces a no-slip condition at the body surface. Simulation results obtained using both boundary treatments were compared against experimental measurements and high-fidelity CFD data for validation. The power-law model demonstrated good agreement with reference data for drag and it predicted complex flow field phenomena correctly, but exhibited discrepancies in wing lift and pressure distributions at high prop tilt angles, highlighting limitations in capturing complex proprotor wake-induced flow separation. The no-slip immersed boundary model overpredicted drag and exhibited excessive flow separation, limiting its applicability to this flow problem, at least at the investigated spatial resolution. The findings highlight the promise of the LBM as an efficient simulation method for quick-turnaround design and analysis of proprotor-wing interactions, including the transition (or conversion) maneuver, while identifying areas for improvement in the explicit power-law wall model to enable more accurate prediction of separated flows and near-wall behavior.