Experimental Investigation of the Coupling Process of Laminar Wings at Their Tips

Abstract

In this paper, we address the influence of geometric parameters relevant to the lateral in-flight coupling of two laminar wings at a Reynolds number of . The aerodynamic loads are determined by means of detailed force and pressure measurements for different wing spacings and angle-of-attack combinations. When the spanwise spacing between the wings is reduced, increased lift and decreased drag coefficients are noted, which are mainly explained by the alteration of wing-tip vortices. We also show that the gap flow developing between both wings at small distances induces a suction effect, that is, strong lateral forces of opposite signs acting on the two wings. When the angles of attack of both wings are varied for a fixed-wing spacing, a strong interaction between the two wings is found to affect the lift and drag coefficients. The results presented in this paper help understand the changes in aerodynamic loads that occur during the wing–tip-coupling process, and thus may promote the design and operation of such procedures in for future multibody aircraft.