Induced side forces at high angles of attack

Abstract

Linear regression techniques are used to establish a quantitative description of side forces on bodies of revolution at high incidence and zero side slip. A data base is assembled concerning the key side force characteristics of maximum measured side force, angle of attack at which it occurs, and minimum angle of incidence at which a side force is observed (onset angle). This information is examined to determine the important trends, and a linear regression model is developed for these quantities to include only those variables which are statistically significant. Results indicate that the peak side force coefficient is a function of Mach number, and only slightly of Reynolds number. Nose fineness is the critical model dimension which suggests that peak side forces are a product of the nose flowfield. Blunting of the nose reduces the magnitude of the side force but the degree of bluntness does not appear to be important. The angle at which the maximum side force occurs is found to be dependent on model length and Mach number, while the onset angle is a function of model length only.