Effect of Wire Trips on the Flow over Slender Body at High Angle of Attack

Abstract

Pressure distributions on slender body were measured in a low-speed wind tunnel at 40° angle of attack. Twin wires longitudinally applied on both sides of the model at an azimuthal orientation 52.5°. Compared with the result of natural transition, the pressure contributions of twin-wire model exhibit a premature transition and an earlier turbulent separation. Behavior of the flow around slender body in post critical Reynolds region can be obtained in a low Reynolds region. Five different sizes of wire were applied in the test, i.e. 0.1, 0.3, 0.5, 0.7 and 1mm in diameter. Through comparing the pressure distributions of model with different wires, it can be concluded that wire diameter only affect the magnitude of initial post critical Reynolds number, rather than the characteristics of the flow around slender body. The thicker the wire is, the earlier turbulence separation appears, thereby accompanying a decrease in the initial post critical Reynolds number.