NASA Technical Reports Server (NTRS) 19900018378: A two dimensional study of rotor/airfoil interaction in hover

by: NASA Technical Reports Server (NTRS)

Publication date: 1988-08-01

Topics: NASA Technical Reports Server (NTRS), AIRFOIL PROFILES, GROUND EFFECT (AERODYNAMICS), HOVERCRAFT GROUND EFFECT MACHINES, HOVERING, INTERACTIONAL AERODYNAMICS, TWO DIMENSIONAL MODELS, PRESSURE DISTRIBUTION, SLIPSTREAMS, TILTING ROTORS, UPPER SURFACE BLOWING, VORTICES, WAKES, Lee, Chyang S.,

Collection: NASA_NTRS_Archive; additional_collections

Language: English

A two dimensional model for the chordwise flow near the wing tip of the tilt rotor in hover is presented. The airfoil is represented by vortex panels and the rotor is modeled by doublet panels. The rotor slipstream and the airfoil wake are simulated by free point vortices. Calculations on a 20 percent thick elliptical airfoil under a uniform rotor inflow are performed. Variations on rotor size, spacing between the rotor and the airfoil, ground effect, and the influence upper surface blowing in download reduction are analyzed. Rotor size has only a minor influence on download when it is small. Increase of the rotor/airfoil spacing causes a gradual decrease on download. Proximity to the ground effectively reduces the download and makes the wake unsteady. The surface blowing changes the whole flow structure and significantly reduces the download within the assumption of a potential solution. Improvement on the present model is recommended to estimate the wall jets induced suction on the airfoil lower surface.