Final Stage of Development of Patterns of Vorticity

Part of Free-surface Wave Interaction with a Horizontal Cylinder,
an M.S. thesis by Peter Oshkai. Department of Mechanical Engineering and Mechanics. Lehigh University.

The final stage of development is indicated in Figure 7c. At relatively deep submergence (top row of images), vortices A', B and D migrate in the clockwise direction in accord with the wave trajectory, and vortex B' appears on the lower surface of the cylinder at N = 19.

For intermediate submergence (middle row), vorticity concentration A, which, unlike the case of deepest submergence, did not collide with the cylinder, is still identifiable. Development of concentration A' in images N = 17 and 19 is closely similar to its development at the deepest submergence. Vorticity pattern B,D retains its identity of two concentrations at N = 17; they appear distinctly separated at N = 19.

At the shallowest submergence, the array of six counterrotating concentrations of vorticity is still identifiable at N = 17, though the peak vorticity levels of each of the concentrations has generally decreased. At N = 19, onset of vorticity concentration B' along the right surface of the cylinder occurs in a fashion analogous to that at intermediate and deep levels of submergence.


pmo2@lehigh.edu