Mean flow and turbulence measurements in the wake of a slender propeller-driven body including effects of pitch angle

Abstract

An experimental study of the turbulent wake produced by a stern-propeller-driven body at pitch angles of 0º and -2° is presented. The effect of an appendage such as a submarine sail to an axisymmetric body is also considered. Mean flow velocities, static pressure, flow angularity, and turbulence quantities are presented at three downstream stations Z/D = 2, 10, and 40. The measurements were taken using a yawhead pressure probe and hot-wire sensors. The testing was conducted in the Virginia Tech 6-foot subsonic tunnel at free-stream Re_D ≃ 4.4 x 10⁵. The addition of the appendage substantially increased the drag on the slender axisymmetric body considered and increased the turbulence level in the region behind the sail. The propeller swirl was also decreased by the presence of the sail. The results for the negative pitch angle indicate further increases in the turbulence intensities and a greater decrease in the swirl behind the sail.