THE UNSTEADY FLOW FIELD ABOUT A RIGHT CIRCULAR CONE IN UNSTEADY FLIGHT

Abstract

Abstract : The inviscid flow field about a right circular cone in unsteady planar flight is analyzed by a perturbation technique which is an extension of Stone's treatment of the cone at small yaw. A solution is found in the form of infinite series in the time rates of change of the pitch rate and angle of attack. The linear stability derivatives as well as 'higher order' stability derivatives are presented for a wide range of cone angles and Mach numbers. The stability derivatives as obtained from this solution are compared to results obtained from second order potential theory, Newtonian impact theory, and an unsteady flow theory due to Zartarian, Hsu, and Ashley. Both the potential theory and the impact theory predict that the stability derivative (angle of attack) approaches a value which is on the order of 10 percent to 20 percent of the stability derivative (pitch rate). Numerical results obtained from the present theory are also compared to ground-test data. The agreement is found to be generally good, although the data in some instances indicate a pronounced Reynolds number effect.