Navier-Stokes Predictions of Dynamic Stability Derivatives: Evaluation of Steady-State Methods

摘要

The prediction of the dynamic stability derivatives, roll damping, Magnus moments, and pitch-damping momentsnwere evaluated for three spin-stabilized projectiles using steady-state computational fluid dynamic calculations.nRoll-damping computational fluid dynamic predictions were found to be very good across the Mach number rangeninvestigated. Magnus moment predictions were very good in the supersonic flight regime but the accuracy varied innthe sub- and transonic flight regime. The best Magnus moment prediction in the subsonic flight regime was for thennon-boat-tailed projectile that did not exhibit highly nonlinear Magnus moments. A primary contribution of thisnpaper is the demonstration that the pitch-damping moment can be adequately predicted via steady-state methods,nrather than resorting to unsteady techniques. The predicted pitch-damping moment compared very well withnexperimental data for the three projectiles investigated. For one configuration, the pitch-damping moment wasnpredicted by several computational fluid dynamic codes, two different steady-state methods, and a time-accuratenplanar pitching motion method. All methods compared very well with each other and to the experimental data.