Computational Prediction of Pitch Damping for Supersonic Blunt Cones

摘要

Methods to predict pitch-damping coefficients (PDCs) of bodies from steady flow computations, avoiding costly time-accurate solutions, have been proposed by Schiff. Lunar coning motion is imposed on the projectile, and the flow governing equations are solved in the rotating framework for which the flow is steady. Coning motion is the motion performed by an object flying at a constant angle of attack with respect to the freestream velocity vector and undergoing rotation at a constant angular velocity about a line parallel to the freestream flow direction passing through the projectile's c.g. Use of a moment expansion then allows prediction of the PDC sum (C_(m_q) + C_(m_α)) from static moment coefficients in the frame of reference for which the flow is steady. Experimental measurements performed by Schiff and Tobak provided additional support for this theory. Previously, much of these aerodynamic data was obtained from either simplified analytical approaches, empirical methods, wind-tunnel testing, or full-scale range firings.