Theoretical Wave Drag and Lift of Thin Supersonic Ring Airfoils
Abstract
An approximate linearized solution is presented for the wave drag and lift of an airfoil generated by rotating a thin supersonic profile about an axis parallel, or nearly parallel, to its chord. The aerodynamic coefficients are obtained from a surface distribution of sources, of strengths proportional to the local airfoil slopes, about a cylinder whose radius and chord equal those of the original ring airfoil. This source distribution satisfies the boundary conditions when the part of the wing within the forward Mach cone from a point on the wing surface departs only slightly from a plane. The solution is therefore accurate for ring airfoils having chords that are small in comparison to the radius of rotation. The lift coefficient of thin supersonic ring airfoils, based on the airfoil-surface area, is one-half the Ackeret value for a two-dimensional wing of infinite span. The drag coefficient is equal to the sum of the Ackeret value for the given profile (with the ring airfoil at zero angle of attack) and the induced drag coefficient. These coefficients are probably within 5 percent of the correct linearized values for ring airfoils whose chord-radius parameter (chord divided by the product of the radius and the cotangent of the Mach angle) is within the range from 0 to 0.20.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1948
- Accession Number
- ADA380756
Entities
People
- Harold Mirels
Organizations
- Glenn Research Center