Aerodynamic Coefficient Derivatives of Sonic Missiles via Slender Body Theory.
NAVAL RESEARCH LAB WASHINGTON D C
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This investigation was initiated to develop analytic procedures for estimating aerodynamic coefficient derivatives for missiles. The analytic estimates will depend primarily on the geometrical configurations of the missiles. The problem of determining the coefficient derivatives becomes reasonably tractable for thin airfoil-body combinations with moderate finite aspect ratios and flying at sonic speeds. Starting with the equations for a perfect gas, a linearization of them is achieved by assuming flow over a thin profile. A further assumption of a speed of Mach 1 gives rise to slender body theory. The problem is thus reduced to a potential boundary value problem in a cross-flow plane. Upon consideration of the total momentum in a cross-flow slab, it is found that the resultant lateral force may be expressed as a countour integral of the velocity potential. The effects of missile angle of attack and control-surface angle are incorporated by way of Neumann-type conditions on the boundary contour. For the special case where the missile cross section is a circle with midwing, there is an analytic solution for the potential-flow problem. For the case where there is an arbitrary missile cross section, a computer program has been developed which addresses the problem using a source distribution approach. Results are given for several sample cross sections. It is shown how the cross-flow results may be applied to a typical missile configuration to obtain the aerodynamic coefficient derivatives. Author
- Guided Missiles
- Fluid Mechanics