Numerical analysis of single-vortex/free-surface interaction

The interaction of a single Lamb vortex with a free surface is analyzed numerically through the use of a finite-difference technique. The individual effects of gravity, viscosity, and surface tension are investigated within the range of the applicability of the phenomenon and the code used. The vortex is allowed to build up to its full strength in a relatively small time and then the evolution of the free surface, streamlines, and other details of the flow are calculated. The results have shown that the smaller the proximity of the vortex to the free surface, the larger the scar produced on its down-wash side. The effect of the surface tension is to reduce the amplitude of the free surface elevation. The viscous effects appear to be relatively small even though the calculations are, out of necessity, confined to a limited range of the governing parameters, as in all finite difference calculationshttp://archive.org/details/numericalanalysi00merrLieutenant, United States NavyApproved for public release; distribution is unlimited