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기술보고서

기술보고서 게시판 내용
타이틀	Supersonic Pitch Damping Predictions of Blunt Entry Vehicles from Static CFD Solutions
저자	Schoenenberger, Mark
Keyword	ANGLE OF ATTACK;; AXISYMMETRIC BODIES;; BLUNT BODIES;; COMPUTATIONAL FLUID DYNAMICS;; DAMPING;; DYNAMIC STABILITY;; MACH NUMBER;; MARS ROVING VEHICLES;; MATHEMATICAL MODELS;; NONLINEARITY;; PITCHING MOMENTS;; STATIC STABILITY;; SUPERSONIC FLOW;; VIKING MARS PROGRAM
URL	http://hdl.handle.net/2060/20130003227
보고서번호	AIAA Paper 2013-0356
발행년도	2013
출처	NTRS (NASA Technical Report Server)
ABSTRACT	A technique for predicting supersonic pitch damping of blunt axisymmetric bodies from static CFD data is presented. The contributions to static pitching moment due to forebody and aftbody pressure distributions are broken out and considered separately. The one-dimension moment equation is cast to model the separate contributions from forebody and aftbody pressures with no traditional damping term included. The aftbody contribution to pitching moment is lagged by a phase angle of the natural oscillation period. This lag represents the time for aftbody wake structures to equilibrate while the body is oscillation. The characteristic equation of this formulation indicates that the lagged backshell moment adds a damping moment equivalent in form to a constant pitch damping term. CFD calculations of the backshell''s contribution to the static pitching moment for a range of angles-of-attack is used to predict pitch damping coefficients. These predictions are compared with ballistic range data taken of the Mars Exploration Rover (MER) capsule and forced oscillation data of the Mars Viking capsule. The lag model appears to capture dynamic stability variation due to backshell geometry as well as Mach number.