Structure of an Axisymmetric Turbulent Boundary Layer with Pressure Gradients*

The axisymmetric turbulent boundary layer of a body of revolution was measured in a wind tunnel. The model studied was the hull of a generic submarine, the DARPA SUBOFF, without its appendages or sail. High dynamic spatial range (in excess of 1,000) particle image velocimetry (PIV) was performed along the model's entire tail region (70 to 95% of body length), where the boundary layer experienced strong pressure gradients and surface curvatures. Surface static pressure measurements and flow statistics from PIV showed agreement with historical data. Further, comparisons of the flow statistics and structures were made between this axisymmetric boundary layer and the canonical flat plate boundary layer. This analysis reveals the combined effects of pressure gradient and surface curvatures on boundary layer development.