Effect of an end plate on surface pressure distributions of two swept wings

A series of wind tunnel tests was conducted to examine how an end plate affects the pressure distributions of two wings with leading edge (LE) sweep angles of 23° and 40°.All the experiments were carried out at a midchord Reynolds number of 8 × 105,covering an angle of attack (AOA) range from-2° to 14°.Static pressure distribution measurements were acquired over the upper surfaces of the wings along three chordwise rows and one spanwise direction at the wing quarter-chord line.The results of the tests confirm that at a particular AOA,increasing the sweep angle causes a noticeable decrease in the upper-surface suction pressure.Furthermore,as the sweep angle increases,the development of a laminar separation bubble near the LEs of the wings takes place at higher AOAs.On the other hand,spanwise pressure measurements show that increasing the wing sweep angle results in forming a stronger vortex on the quarter-chord line which has lower sensitivity to AOA variation and remains substantially attached to the wing surface for higher AOAs than that can be achieved in the case of a lower sweep angle.In addition,data obtained indicate that installing an end plate further reinforces the spanwise flow over the wing surface,thus affecting the pressure distribution.