An Investigation of Tip-Vortex Turbulence Structure using Large-Eddy Simulation

In this effort, the tip vortex behind a rectangular plan-form lifting fin with a cavitation-relevant airfoil section (NACA-66 mod) is studied using Large Eddy Simulation (LES) at a free-stream Reynolds number of 500,000. Elementary flow quantities (lift, drag, velocities) are compared with measurements made in the Garfield Thomas Water Tunnel (GTWT) 12-inch circular test-section. Good agreement is seen with the measured lift and drag. The characteristic 45-degree lag between the mean strain rate and the Reynolds stress components in the plane of the tip vortex is observed. The calculated flow field provides insight into the turbulent structure of the tip vortex for this fin.