Experimental and Theoretical Investigation of Factors Affecting Fin-Body Interference.

Abstract : A comprehensive series of wind-tunnel experiments were conducted to determine the static-lateral stability characteristics of a systematic series of submarine-type fin-body combinations. The effects of body-boundary layer and sidewash, fin-aspect ratio, fin-taper ratio, and diameter-span ratio on the total forces and moments of the fin-body combinations as well as on the fins in the presence of the bodies were evaluated. Measurements were also made to define the body boundary layer and sidewash in the vicinity occupied by the fins. Visualization of the flow behind the body and body-fairwater combination was observed by means of a tuft grid. The results of the investigation are presented in the form of plots and tabulations of the nondimensional force and moment coefficients, static stability derivatives and mutual interference factors. Also, comparisons of the results are made with theory and calculations based on a modified lifting surface method. (Author)