Published 6 issues per year
ISSN Print: 1948-2590
ISSN Online: 1948-2604
LIFT AND INDUCED DRAG OF A FINITE-SPAN WING IN A FLOW OF VISCOUS COMPRESSIBLE GAS AT SUBSONIC SPEEDS
ABSTRACT
The method of transformation of the law of conservation of momentum for a continuum, applied by Zhukovsky [1] in the derivation of a profile lift theorem in an ideal incompressible fluid, is generalized for a spatial motion of a finite-span wing in a compressible viscous gas. As a result, we obtain an expression for the main vector of aerodynamic forces, which is the analog of the Zhukovsky theorem, but containing the side force and resistance force besides the lift. A correlation between the resistance force and the lift force is shown. An approximate analytical expression for the wing-induced drag in a viscous medium is obtained and the physical nature of its occurrence is studied. Limit as Re→∞, the Prandtl formula is for a wing-induced drag in an ideal fluid.