Wind tunnel investigation of a low speed oblique plate

An integrated method of oil flow visualization and smoke visualization was used to study an oblique plate with different sweep angles at different angles of attack and force measurements were also conducted. The oil flow visualization reveals the flow separation and reattachment characteristics on the surface of the oblique plate. The smoke visualization shows the three dimensional vortex structure above the oblique plate so as to demonstrate and interpret the flow pattern captured in the oil flow visualization. The behaviors of lift and rolling moment were acquired by the force measurements. The experiment shows that, with increasing sweep angles, a spanwise vortex flow is generated in the middle and backswept region of the plate when it is positioned at small attack angles, which offers a relatively small positive rolling moment. On the other hand, at high angles of attack, a strong vortex starts from the forward swept apex and develops along the spanwise direction, whose range of influence extends from the forward swept to the back swept section, causing the rolling moments to decrease at first and then increase again with increasing sweep angles.