Numerical simulation of individual components of pitch-damping coefficient sum

An approach for predicting the direct damping derivatives that formed the pitch-damping sum was presented. Application of the technique was made to the axisymmetric projectile configuration as well as the non-axisymmetric winged vehicle. The plunging derivatives and pitch-damping sum were obtained using forced heave and angular motions that excited the different angular rates under the basis of Etkin's unsteady aerodynamic model. The numerical calculation method of pitch damping derivatives was studied. The investigations of HBS and Basic Finner standard model and Hyflex show that the predicted pitch-damping coefficient sum obtained by adding the individually determined coefficients is in excellent agreement with the pitch-damping coefficient sum predicted by forced angular motions and with experimental data, and the variation of the damping derivative components with the location of gravity center is also consistent with the theoretical prediction. As for winged vehicle, the plunging derivative plays a leading role in the pitch-damping coefficient sum in the supersonic region.