Accession Number:

ADA537734

Title:

Self-Excited Roll Oscillations of Non-Slender Wings

Descriptive Note:

Final rept. 1 Jul 2006-1 Jul 2009

Corporate Author:

BATH UNIV (UNITED KINGDOM) DEPT OF MECHANICAL ENGINEERING

Personal Author(s):

Report Date:

2010-03-01

Pagination or Media Count:

38.0

Abstract:

The main objective of this research is to understand the free-to-roll aerodynamics and self-excited roll oscillations of low aspect ratio wings. Generic thin, flat-plate wing planforms for unmanned air vehicles and micro air vehicles were considered. Slender and nonslender delta wings with sweep angles between 40-deg and 70-deg, cropped delta wings, rectangular wings with aspect ratios of AR 2 and 4, Zimmerman, and elliptical wings were investigated. Measurements of roll history, flow visualization, and PIV measurements were conducted in the free-to-roll experiments in a wind tunnel. Nonzero trim roll angles and self-induced roll oscillations were observed for most of the wings. Leading-edge vortices, tip vortices and separation bubbles play an important role in the free-to-roll aerodynamics. Hysteresis and time lag effects are behind the observed roll oscillations. The results may be useful in improving the maneuverability and gust response of unmanned air vehicles.

Subject Categories:

  • Electricity and Magnetism
  • Fluid Mechanics
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE