© 1948 by Oxford University Press
THE FLAT DELTA WING AT INCIDENCE, AT SUPERSONIC SPEEDS, WHEN THE LEADING EDGES LIE OUTSIDE THE MACH CONE OF THE VERTEX
( Imperial College London, S.W.7 )
H. J. Stewart's (1) analysis using the linearized equation of supersonic flows for finding the lift of a flat delta wing at supersonic speeds when the leading edges of the wing lie within the Mach cone of the vertex, is extended to the case when the leading edges of the wing lie outside the Mach cone of the vertex.
From the condition specified on the wing, Fourier expansions are found for the downward vertical induced velocity component w, outside and on the Mach cone of the vertex. The constant velocities on the wing, outside the Mach cone of the vertex, are deduced from the shock-wave relations across the Mach planes of the leading edges. Fourier expansions are found for the axial and transverse disturbance velocities u, v. the constancy of these velocities, in regions outside the Mach cone, being deduced from the vorticity relations.
The methods of the complex variable, used by Stewart, are used to obtain the induced velocity components inside the Mach cone of the vertex. The solution for the velocity component w is found from the conditions to be satisfied on the wing and on the Mach cone of the vertex. Hence, by using the vorticity relations and the Cauchy-Riemann relations, the solutions for the velocities u, v are found.
The pressure distribution on the wing is deduced, and the total lift calculated, by integrating the pressure difference over the surface of the wing. The lift coefficient, based on area, is found to be independent of the angle of the wing. The corresponding drag coefficient is also found.