Asymmetric distributions of base pressure on an axi-symmetric body

The work to be described was planned as the first stage of an investigation of the effects of streamwise vortices on base pressure. An axi-symmetric blunt-based body was used, consisting of a cylindrical portion with a semiellipsoidal nose. The intention was to mount strakes or semi-delta wings at incidence on the sides of the body to produce vortices and to measure the effects of these on the base pressure. The base of the body was fitted with 37 pressure tappings so that local variations of base pressure could be explored. It was found that for the body at zero incidence and yaw, without any strakes or wings, there was great difficulty in obtaining an axi-symmetric distribution of pressure on the base.