SUBSONIC OSCILLATORY OR STEADY AIRLOADS ON WINGS WITH CONTROL SURFACES AND OTHER DISCONTINUITIES.
Scientific Interim rept.,
STANFORD UNIV CALIF DEPT OF AERONAUTICS AND ASTRONAUTICS
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Detailed procedures are described for numerical calculation of the lifting pressure distribution on a wing or tail with control surfaces or other discontinuities, oscillating in a subsonic main stream. The basis of the solution is the integral equation of a pressure doublet sheet, linearized under the hypothesis of small disturbances. The key discovery permitting a new approach to this problem is Landahls theorem, which shows that the magnitude of the pressure singularity along a discontinuity line such as a control leading or side edge is directly related to the upwash discontinuity at that edge. Two known exact solutions are shown to verify Landahls result. The report focuses on symmetrical motion of a pair of symmetrically-disposed trailing-edge controls with rectilinear, swept leading edges. The extensions to other cases, such as antisymmetrical motion, leading-edge flaps, controls with aerodynamic balance, etc., are discussed. Brief illustrations are presented on the use of matched asymptotic expansions in other discontinuity situations which may arise in lifting surface theory. Author
- Fluid Mechanics