Mid-Fidelity Investigation of the Proprotor-Wing Aerodynamic Interactions across the Tiltrotor Conversion Maneuver

This paper assesses the capabilities and limitations of mid-fidelity computational fluid dynamics (CFD) approaches when resolving the complex aerodynamic interactions for a generic model-scale proprotor-wing configuration across the tiltrotor conversion maneuver. The Helios mid-fidelity Reduced Order Aerodynamic Model (ROAM) is evaluated against prior extensively validated high-fidelity Helios-OVERFLOW assessments for the proprotor-wing configuration. The ROAM actuator line model (ALM), which represents the proprotor blade via source terms injected into the off-body Cartesian domain, is assessed for the isolated proprotor configuration at several mesh resolutions to understand the requirements to accurately resolve the proprotor physics across the conversion maneuver. The impact of adaptive mesh refinement (AMR) on ROAM's ability to resolve the proprotor physics is also investigated. Next, the flow characteristics and wing loads are evaluated using the ROAM immersed boundary method (IBM) for the isolated wing. The sensitivity of the ROAM IBM predictions to mesh resolution and boundary condition selection is quantified in these assessments. Leveraging the findings from the isolated proprotor and isolated wing assessments, the ROAM ALM and IBM are applied together to model the proprotor-wing configuration, enabling an evaluation into the ability for mid-fidelity methods to resolve the complex aerodynamic interactions across the tiltrotor conversion maneuver.