Flow interactions around a rapidly-pitching MAV wing

Ryan Randall, Lee Wilson, Sergey Shkarayev

Research output: Contribution to conferencePaper

4 Scopus citations

Abstract

This study was conducted to visually investigate flows related to fixed-wing vertical-takeoff-and-landing micro air vehicles, using the smoke-wire technique. In particular, the study examines transition between forward flight and near-hover. The experimental model consists of a rigid Zimmerman wing and a propulsion system with contra-rotating propellers arranged in a tractor configuration. The model was pitched about the wing's aerodynamic center at approximately constant rates using a five-axis robotic arm. Constant-rate pitching angles spanned 20 to 70 degrees. Five pitching-rates were used, along with three propulsive settings. Several observations were made. Contra-rotating slipstreams generally cause a delay in the onset of trailing-edge vortex-shedding within their vicinities. Higher nose-up pitching-rates generally lead to greater trailing-edge vortex-shedding frequency. Nose-up pitching without a slipstream can lead to the development of a traditional dynamic-stall leading-edge vortex (LEV), delaying stall and increasing wing lift. During nose-up pitching a slipstream can drive periodically-shed leading-edge vortices into a larger vortical-structure that circulates over the upper-surface of a wing in a fashion similar to that of a traditional dynamic-stall LEV. At lower nose-up pitching-rates LEVs form at lower angle of attack. As a slipstream strengthens a few things occur: separation wakes diminish, separation occurs at a higher AOA and downward flow-deflection increases. Similar effects are observed for nose-up pitching, while nose-down pitching produces the opposite effects.

Original languageEnglish (US)
DOIs
StatePublished - Dec 1 2012
Event50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition - Nashville, TN, United States
Duration: Jan 9 2012Jan 12 2012

Other

Other50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition
CountryUnited States
CityNashville, TN
Period1/9/121/12/12

ASJC Scopus subject areas

  • Aerospace Engineering

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    Randall, R., Wilson, L., & Shkarayev, S. (2012). Flow interactions around a rapidly-pitching MAV wing. Paper presented at 50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, Nashville, TN, United States. https://doi.org/10.2514/6.2012-667