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Optics and AcousticsAcoustics

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

Authors: Paul Weinacht; James DeSpirito; Sidra I Silton; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
 
Abstract: 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 was for the square-base projectile that did not exhibit highly nonlinear Magnus moments. A primary contribution of this report is the demonstration that the pitch-damping moment can be adequately predicted via steady-state methods rather than resorting to unsteady techniques. The predicted pitch-damping moment compared very well to experimental data for the three projectiles investigated. For one configuration, the pitch-damping moment was predicted by several CFD codes, two different steady-state methods, and a time-accurate planar pitching motion method. All methods compared very well to each other and to the experimental data.

Limitations: APPROVED FOR PUBLIC RELEASE
Description: Final rept. Jan-Dec 2007
Pages: 44
Report Date: Sep-2008
Report Number: A574194
Keywords relating to this report:
*AERODYNAMICS
*COMPUTATIONAL FLUID DYNAMICS
*DAMPING
*DYNAMICS
*NAVIER STOKES EQUATIONS
*Stability
*STEADY STATE
ACOUSTICS
EXPERIMENTAL DATA
FLIGHT ENVELOPE
MACH NUMBER
MAGNUS EFFECT
MOMENTS
Pitch_Inclination_
PREDICTIONS
PROJECTILES
ROLL
SUBSONIC FLIGHT
SUPERSONIC FLIGHT
TRANSONIC FLIGHT
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