A Study on the Dynamic Stall Characteristics of an Elliptical Airfoil by Flow Pattern Measured by PIV

Lee, Ki-Young; Sohn, Myong-Hwan; Jung, Hyong-Seok

Journal of the Korea Institute of Military Science and Technology 2005;8(3):116-123.

Ki-Young Lee, Myong-Hwan Sohn, Hyong-Seok Jung

¹
²

PIV 측정 흐름형태에 의한 타원형 날개꼴의 동적 실속 특성 연구

이기영, 손명환, 정형석

¹공군사관학교 기계공학과
²공군사관학교 항공우주공학과

Abstract

An experimental investigation on the static and dynamic stall characteristics of elliptic airfoil was performed by PIV velocity field measurements. The flow Reynolds number was $3.13{ imes}10^5$ and the reduced frequency of the pitch oscillation ranged from 0.075 to 0.125. The onset of static stall was caused by boundary layer separation which started at the trailing edge and progressed toward the leading edge. However, dynamic stall was caused by the vortex shed at the leading edge region and the flow field showed a vortex dominated flow with turbulent separation and alternate vortex shedding. The increase of reduced frequency increased the dynamic stall angle of attack and intensified the flow hysteresis in the down-stroke phase.

Key Words: Dynamic Stall, Pitch Oscillation, Elliptic Airfoil, Vortex Dominated Flow, Reduced Frequency