The rotor hub system is recognized as one of the primary contributors to helicopter parasite drag and is one of the inherent limiters to maximum helicopter forward-flight speed. Despite its importance for the performance of rotorcraft, complex bluff-body flows of the rotor hub have received only intermittent attention since the first studies in the 1950s. This work presents a comprehensive review of experimental and computational research over the past 60 years on rotor hub flows and describes the challenges associated with component and interference drag, effect of the hub near wake on pylon and fuselage flows, and the long-age wake of rotor hubs at high Reynolds number with the associated size and strength of flow structures that interact with the empennage. Computational technology is assessed as an emerging design tool for hub/pylon design, and, with its ability to capture downstream flow unsteadiness, empennage/tail surface aeroelasticity and controllability. The work concludes with recommendations of future experimental and computational evaluations to advance the community's understanding of rotor hub flows and mitigation of its adverse effects for future rotorcraft.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Aerospace Engineering
- Mechanics of Materials
- Mechanical Engineering