ESDU 89014 C-1993 NORMAL FORCE@ PITCHING MOMENT AND SIDE FORCE OF FOREBODY-CYLINDER COMBINATIONS FOR ANGLES OF ATTACK UP TO 90 DEGREES AND MACH NUMBERS UP TO 5
INTRODUCTION This Item provides a simple@ semi-empirical means of estimating the normal force and pitching moment of axisymmetric forebody-cylinder combinations at angles of attack up to 90 degrees and Mach numbers up to 5. The method requires estimates for the normal-force-curve and pitching-moment-curve slopes at zero angle of attack from Item No. 89008 (Derivation 39) and geometrical parameters from Item No. 77028 (Reference 46). In subsonic and transonic flow at high angles of attack@ asymmetric vortex flow may occur on the leeward side of the body. This phenomenon@ which is known to depend on such minor factors as small imperfections at the nose@ has the effect of producing an out-of-plane force distribution that can result in large side forces and yawing moments. A qualitative description of the nature of asymmetric vortex flow is given in Section 3 and an envelope of resulting maximum overall side force is given in Section 5. Sections 4@ 5 and 6 consider the effects of Reynolds number@ Mach number and forebody blunting respectively@ based on the work covered in Derivations 18@ 22@ 26@ 27@ 32@ 33@ 35 and 38 and References 41 to 45 and 47 to 50. Section 7 describes the predictions of normal force and pitching moment@ which are illustrated by a worked example in Section 10. Section 8 provides a guide to the applicability and accuracy of the prediction method. The effects of conical boat-tailing on normal force and pitching moment are given in Item No. 87033 (Reference 51). The method of this Item@ together with the effects of conical boat-tailing@ is incorporated in a computer program written by the Computer Products Group of ESDU International (see Item No. 90034; Reference 52)@ available on diskette in the Aerodynamics Software Volume and on CD-Rom.
ESDU 89014 C-1993 history
1993ESDU 89014 C-1993 NORMAL FORCE@ PITCHING MOMENT AND SIDE FORCE OF FOREBODY-CYLINDER COMBINATIONS FOR ANGLES OF ATTACK UP TO 90 DEGREES AND MACH NUMBERS UP TO 5