Statistics of a fully developed turbulent pipe flow perturbed by a streamlined axisymmetric body

A fully developed turbulent pipe flow was perturbed by a streamlined axisymmetric body to study the effects of pressure gradient and streamline curvature. Measurements were taken in a water pipe using PIV at Re_τ≈3400 and in the Princeton Superpipe facility using a nanoscale hot-wire probe with Re_τ up to 100000. Behaviors of the mean velocity and the axial turbulence intensity are explored both at the pipe wall and at the insert body, as well as in a streamline coordinate system. Changes in the statistics compared to canonical pipe flows are clearly correlated with various pressure gradients and streamline curvatures. These changes will be reconciled with the observations from turbulent coherent structures in the same flows. We will also discuss the statistics in terms of turbulence production and their implications for turbulence scaling incorporating pressure and curvature parameters.