Hydrodynamic Loads on an Oscillating Circular Cylinder in a Shear-Layer Fluid under Ice Cover

The linear two-dimensional problem of steady-state oscillations of a circular cylinder in the fluid under an ice cover with a shear near-surface layer is solved. The ice cover is modeled by a thin elastic plate of constant thickness. The lower fluid layer contains a circular cylinder oscillating at a given frequency. The presence of the shear layer leads to the appearance of blocking points in the dispersion curves, at which the group velocity of the developing flexural-gravity waves vanishes. The linear approximation becomes unsuitable in the vicinity of these points. Using multipole expansions, the dependences of the hydrodynamic load (added mass and damping coefficients) on the characteristics of the ice cover and shear flow, the oscillation frequency, and the cylinder immersion depth are investigated. It is found that the diagonal added mass coefficients become negative at small distances of the cylinder from the interface and at low oscillation frequencies.