WAKE DEVELOPMENT IN TURBULENT SUBSONIC AXISYMMETRICAL FLOWS

The development of the wake velocity and turbulence profiles behind a cylindrical blunt based body aligned with a subsonic uniform stream wa s experimentally investigated as a function of the momentum thickness of the approaching boundary layer and the transfer of mass into the re circulating region. Measurements were made just outside of the recircu lating region at distances of 1.5, 2 and 3 diameters downstream of the cylinder. Results indicate that, even at these short distances from t he cylinder base, the velocity profiles are similar. They also show th at the width of the wake increases with the thickness of the boundary layer while the velocity at the centerline decreases. Near wake mass t ransfer was found to alter centerline velocities while the width of th e wake was not significantly altered. Wake centerline velocity develop ment as a function of boundary layer thickness is presented for distan ces up to three diameters from the base.