Measurement of the drag of various three-dimensional excrescences in turbulent boundary layers

Measurements are described of the drags of various forms of three-dimensional excrescence mounted on balances installed in the walls of the working section of the RAE 8 ft x 8 ft wind tunnel. The tests cover a range of Mach numbers between 0·2 and 2·8 and a range of Reynolds number. The excrescences tested include circular cylinders and wings mounted normal to the surface, fairing shapes and mushroom shaped rivet heads. For excrescences which were small compared with the boundary-layer thickness the scale effects were correlated in terms of the wall variables of the turbulent boundary layer. For circular cylinders and wings which protruded well into or beyond the boundary layer the drag may be determined by using a drag defect relationship. The fairings tested comprised half-bodies of revolution with pointed or rounded ends and bodies of rectangular, including square, section with pointed ends.