Distortion of Turbulent Pipe Flow by an Axisymmetric Body*

To better understand the effects of pressure gradient, streamline convergence/divergence, and streamline curvature on turbulence in wall-bounded flows, a body-of-revolution (BOR) is placed on the axis of the Superpipe at Princeton University. Measurements using a nano-scale thermal anemometry probe (NSTAP) are made in the flow over the body and in the wake recovery region. Mean flow, Reynolds normal stress, and spectra are presented for a pipe flow Reynolds number of 1x10^6 and a BOR with a blockage ratio of 2/9. Spectra show that in the bow region, the largest motions in the turbulence scale with local bulk velocity and the spacing between the pipe wall and BOR. In the stern region, the adverse pressure gradient and expanding flow enhances the turbulence and causes a shift in energy content towards larger scales.