Near-field tip vortex behind a swept wing model

You are here: Homepage > Search

Near-field tip vortex behind a swept wing model

Gerontakos, P. / Lee, T.

The near-field flow structure of a tip vortex behind a sweptback and tapered NACA 0015 wing was investigated and compared with a rectangular wing at the same lift force and Re=1.81x10⁵. The tangential velocity decreased with the downstream distance while increased with the airfoil incidence. The core radius was about 3% of the root chord c_r, regardless of the downstream distance and the angle of attack alpha for alpha < 8 deg. The core axial velocity was always wake-like. The core Gamma_c and total Gamma_o circulation of the tip vortex remained nearly constant up to x/c_r = 3.5 and had a Gamma_c/Gamma_o ratio of 0.63. The total circulation of the tip vortex accounted for only about 40% of the bound root circulation Gamma_b. For a rectangular wing, the axial flow exhibited islands of wake- and jet-like velocity distributions with Gamma_c/Gamma_o = 0.75 and Gamma_o/Gamma_b = 0.70. For the sweptback and tapered wing tested, the inner region of the tip vortex flow exhibited a self-similar behavior for x/c_r = 1.0. The lift force computed from the spanwise circulation distributions agreed well with the force-balance data. A large difference in the lift-induced drag was, however, observed between the wake integral method and the inviscid lifting-line theory.