Session MA - Turbulent Boundary Layers V.
MIXED session, Tuesday afternoon, November 23
Grand I, Westin Seattle
Experiments involving drag and high resolution stereo-PIV measurements were made on long, small diameter cylinders in the High Speed Tow Basin at NSWCCD. The cylinders were approximately neutrally buoyant and were towed at speeds ranging from 3.9 to 15.5 m/s. The objective of the investigation is to determine the effect of transverse curvature on axisymmetric turbulent boundary layers for cylinders with radius a=0.45 mm, 1.25 mm and 18 mm and lengths up to 152 m. Results will be presented for values of \delta /a ranging from 1 to 150. Images were acquired over the entire length of the cylinders with approximately 40 instantaneous three-dimensional vector fields obtained for each location. The mean wall shear stress \tau_w and the momentum thickness \theta are computed from mean velocity profiles. In addition, the total drag on the cylinder is used to determine the total mean \tau _w on the cylinder and the maximum \theta using an expression derived from a standard control volume analysis. Results show that \tau _w and \theta are highly dependent on the transverse curvature for the tested speeds