High Reynolds Number Turbulence

The objectives of the grant were to provide a systematic study to fill the gap between existing research on low Reynolds number turbulent flows to the kinds of turbulent flows encountered on full-scale vehicles. We report specifically on 1 the behavior of wakes at high Reynolds numbers with increasing complexity, varying from axisymmetric wakes, to wakes typical of appended undersea platforms and 2 the effects of roughness at high Reynolds numbers. We have gained a better understanding of complex flow interactions in wakes typical of naval platform flow fields, especially wakes with concentrated regions of streamwise vorticity. We have also made progress in the understanding of high Reynolds number flows over rough surfaces, especially pipes and flat plates with roughness that relate to marine surfaces. We expect these studies to lead to improved flow prediction and improved flow control. The work was performed in two unique facilities the Superpipe and the High Reynolds number Test Facility HRTF that can obtain very high Reynolds numbers on a laboratory scale using compressed air as the working fluid.