SURFACE-WAVE DAMPING IN A CIRCULAR-CYLINDER WITH A FIXED CONTACT LINE

The natural frequencies and damping ratios for surface waves in a circ ular cylinder are calculated on the assumptions of a fixed contact lin e, Stokes boundary layers, and either a clean or a fully contaminated surface. These theoretical predictions are compared with the measureme nts for the first six modes in a brimfull, sharp-edged cylinder of rad ius 2.77 cm and depth 3.80 cm. The differences between the predicted a nd observed frequencies were less than 0.5% for all but the fundamenta l axisymmetric mode with a clean surface. The difference between the p redicted and observed damping ratio for the dominant mode with a clean surface was 20%; this difference was significantly larger for the hig her modes with a clean surface and for all of the modes with a contami nated surface.