A Model Problem of the Design and Aerodynamical Calculation of the Gliding Wing Airfoil of a Wing-in-Ground Vehicle

Abstract

The problem of the design and aerodynamical calculation of a wing airfoil whose trailing edge glides over a plane horizontal surface is formulated and solved. The known airfoil undersurface is a rectilinear segment forming a given angle with the ground surface, while the upper surface is sought on the basis of a preassigned velocity distribution. This distribution is taken from a class of hydrodynamically advantageous distributions ensuring separationless flow around the airfoil within the framework of the mathematical flow model adopted. The problem is reduced to a mixed boundary value problem in a half-plane and solved analytically. For calculating the lift coefficient the assumption of a thin jetlet flowing between the horizontal region of the airfoil contour and the ground surface is introduced. The effect of the law of pressure decrease along the jetlet, from the stagnation to the exit value, on the lift coefficient is studied. On the basis of the calculations performed a conclusion is drawn concerning the influence of the rectilinear region slope on the airfoil shape; it is also shown how the slope and the value of the maximum velocity on the airfoil affect its shape and the lift coefficient.