The aerodynamic coefficients of the 7-cal. U.S. Army-Navy Spinner Rocket were characterized using computational fluid dynamic (CFD) calculations and validated using archival experimental data. The static aerodynamic coefficients, roll-damping, and pitch-damping moments were accurately predicted by steady-state Reynolds-averaged Navier-Stokes (RANS) as well as unsteady hybrid RANS/large-eddy simulation (LES) CFD. The Magnus moment was overpredicted in the subsonic and transonic regime. Unsteady RANS/LES computations did not improve the prediction of Magnus ...
The prediction of the dynamic stability derivatives-roll-damping, Magnus, and pitch-damping moments-were evaluated for three spin-stabilized projectiles using steady-state computational fluid dynamic (CFD) calculations. Roll-damping CFD predictions were found to be very good across the Mach number range investigated. Magnus moment predictions were very good in the supersonic flight regime; however, the accuracy varied in the subsonic and transonic flight regime. The best Magnus moment prediction in the subsonic flight regime ...
The report describes both experimental and computational fluid dynamic (CFD) characterizations of acoustic pressure wave travel through a level-dependent hearing protection device, or earplug. The Army's Combat Arms Earplug (CAE) was the device evaluated. Experimental real-ear attenuation at threshold measurements compared very well with design specifications for the CAE. Experimental continuous noise measurements showed higher than desired attenuation in the 1 - to 4-kHz range. Experimental impulse tests provided dynamic ...
Computational fluid dynamic simulations (CFD) were used to predict the aerodynamic coefficients and flow field over a spinstabilized, 25-mm, sub-caliber training projectile. The primary objective of the investigation was to determine the CFD parameters necessary for the accurate prediction of the Magnus moment and roll damping of a spin-stabilized projectile. Archival experimental data was used to validate the numerical calculations. The Mach number range investigated was from 0.4 to 4.5. ...
Computational fluid dynamic simulations were used to compute the aerodynamic coefficients of a body-alone missile and a planar fin missile in the presence of a wind tunnel sting. The investigation was an extension to a previous investigation in which the computed forebody axial force did not compare well with experimental wind tunnel data, while all other forces and moments showed excellent agreement. The current investigation showed that the computed results ...
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