Aerodynamics of pitching delta wing with yaw angle

In this study, a slender delta wing with 70° sweep angle, Λ was oscillated about its mid-cord in a vertical plane according to the equation α(t)=αm+αosin(ωet). The values of mean angle of attack, αm were taken as 25°, 30° and 35°. The yaw angle, β was varied over the range of 0°≤ β ≤ 16°. The delta wing was sinusoidally pitched within the range of period of time, Te=2π/ωe, 5s≤ Te ≤60s and the reduced frequencies were set as K=0.16, 0.25, 0.49, 1.96 and lastly amplitude of pitching motions was varied within the range of ±5°≤ αo ≤ ±10°. The main aim of this study is to observe the effect of pitching motion of delta wing on the formation of vortex breakdown and structures of vortical flow downstream of vortex breakdown under yaw angle, β using a dye visualization and the particle image velocimetry (PIV) technique. Leading edge vortex breakdown position on the windward side moves towards the apex of the delta wing and vorticity concentrations spread over the most part of the delta wing. But the other leading edge vortex on the other side moves in free-stream flow direction without bursting at different yaw angles, β.