Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)September 2006 ARL-RP-131 SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTESA reprint from the AIAA Atmospheric Flight Mechanics Conference and Exhibit, 16-19 August 2004, Providence, RI. ABSTRACTComputational 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. Steady state CFD calculations predicted the drag, normal force, pitching moment, and normal force center of pressure very well-to within 10% of the experimental data. Time-accurate, detached-eddy simulations were found necessary to predict the Magnus moment in the subsonic and transonic flow regimes. Steady state CFD was found adequate to calculate the roll damping, which was predicted to within 15% of the experimental data in both steady state and time accurate calculations. SUBJECT TERMS CFD Computation of Magnus Moment and Roll Damping Moment of a Spinning ProjectileJames DeSpirito * and Karen R. Heavey † U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005-5066Computational fluid dynamic simulations (CFD) were used to predict the aerodynamic coefficients and flow field over a spin-stabilized, 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. Steady state CFD calculations predicted the drag, normal force, pitching m...

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This paper describes a computational study undertaken, as part of a grand challenge project, to consider the aerodynamic effect of micro-adaptive flow control as a means to provide the divert authority needed to maneuver a projectile at a low subsonic speed. A time-accurate Navier -Stokes computational technique has been used to obtain numerical solutions for the unsteady micro-jet-interaction flow field for the axisymmetric projectile body at subsonic speeds, Mach ¼ 0.11 and 0.24 and angles of attack, 0-48. Numerical solutions have been obtained using both Reynolds-Averaged Navier -Stokes (RANS) and a hybrid RANS/Large Eddy Simulation (LES) turbulence models. Unsteady numerical results show the effect of the jet on the flow field and the aerodynamic coefficients, in particular the lift force. This research has provided an increased fundamental understanding of the complex, three-dimensional (3D), time-dependent, aerodynamic interactions associated with micro-jet control for yawing spin-stabilized munitions.

Thispaper describes a multidisciplinary computational study undertaken to model the flight trajectories and the free-flight aerodynamics of finned projectiles both with and without control maneuvers. Advanced computational capabilities in computational fluid dynamics (CFD), rigid body dynamics (RBD) and flight control system (FCS) have been successfully fully coupled on high performance computing (HPC) platforms for physics-based "Virtual Fly-Outs" of munitions. Timeaccurate Navier-Stokes computations have been performed with the commercial CFD++ software to compute the unsteady aerodynamics associated with the free flight of finned projectiles using an advanced scalable unstructured flow solver on a highly parallel Linux Cluster. Progress made in the exploration of new techniques to efficiently generate a complete aerodynamic description consisting of both static and dynamic aerodynamic coefficients for projectile flight dynamic modeling is described. A new procedure that uses timeaccurate sweeps allows rapid generation of static aerodynamic coefficients. Another method uses an unsteady, time accurate CFD simulation that is tightly coupled to a RBD projectile flight dynamic simulation and can generate both static and dynamic coefficients. A set of short time snippets of simulated projectile motion at different Mach numbers is computed using the integrated CFD/RBD/FCS software and employed as baseline data. The technique is being exercised on a finned and a canard-controlled projectile. The effect of canard angle deflection on the aerodynamics of the canard controlled projectile is currently being computed using the virtual fly out method and the CFD/RBD/FCS software.