Unsteady Aerodynamics for Advanced Configurations. Part III. Elliptic-Conical Wing in Linearized Unsteady Transonic Flow

摘要

Pressure distributions were calculated for an elliptic cone performing plunging oscillations at sonic speed. The objective was to study the effect of blunt leading edges and wing thickness. Second order expressions in terms of the parameter (frequency times aspect ratio squared) for velocity potentials, pressure coefficients, and total lift and moment were derived using an iteration procedure and extended for unsteady transonic flow. The results indicate the possibility of developing simple formulas which will give accurate corrections throughout a wide speed range for the effects of leading-edge bluntness on airfoil pressure distributions. An extension of the analysis to account for pitching oscillations or to any flexible vibration mode, involving only chordwise deformations, would be straightforward but laborious. Also, one could treat without much additional difficulty planforms with curved leading edges. The possibility of treatment of flexible vibration modes, involving spanwise deformations, would depend upon successful evaluation of appropriate modifications of integrals contained in the report. (Author)