Estimation of stability derivative for wedges and wings in supersonic and hypersonic flow

Abstract

Present work contains an analytical method derived using Ghoshs Hypersonic similitude to predict the aerodynamic stability derivatives of a Planar Wedge A similitude has been obtained for a planar wedge with attached bow shock at high incidence in Hypersonic and Supersonic flow A strip theory in which flow at span wise location is two dimensional developed by Ghosh is being used This combines with the similitude to lead to a piston theory which gives closed form of solutions for unsteady derivatives in pitch Substantially the same results as the theory of Liu and Hui are obtained with remarkable computational ease for some special cases newlineFurther this theory is extended to predict the aerodynamic stability derivatives of a Planar Wedge in the Newtonian limit The present theory predicts the stability derivatives of a planar wedge for a wide range of geometrical and flow parameters The knowledge of these stability derivatives is essential to freeze and arrive at the geometrical as well as the kinematic similarity parameters before we go for exhaustive computations and experimental studies The present method predicts the stability derivatives in pitch for a planar wedge which is very handy at the design stage newlineFrom the results it is found that stiffness and damping derivatives in pitch increases linearly up to angle of attack twenty five degrees and then non linearity creeps in The Present theory is valid only for attached shock case Effects of wave reflection and viscosity have not been taken into account Effect of leading edge bluntness has been neglected Results have been obtained for supersonic and hypersonic flow of perfect gases over a wide range of angle of attack sweep angle aspect ratio and the Mach number newline