BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Generation of wave motion in fluid with inhomogeneous ice cover - Izolda Sturova (Lavrentyev Institute of Hydrodynamics) DTSTART:20171110T143000Z DTEND:20171110T150000Z UID:TALK94846@talks.cam.ac.uk CONTACT:INI IT DESCRIPTION:The dynamic perturbations occurring in fluid and ice cov er as a result of the action ofmechanical external force have been thoroug hly studied in the linear treatment for aninfinitely extended homogeneous ice cover\, which is modeled by a thin isotropicelastic plate floating on the surface of a fluid of constant depth. In reality\, the icecover is not homogeneous\, since it can cover not the entire upper boundary of a fluid \,but only its part\, and also there may be the cracks and the patches of ice-free water init. The effect of such complex boundary conditions on the wave motion is in the initialstage of the study.

We present a revi ew of the solutions for several 2-D and 3-D problems. The timeharmonicprob lem describing small oscillations (sway\, heave and roll) of a horizontalc ylinder is considered for four classes of hydroelastic system: i) a floati ng semiinfiniteelastic plate\; ii) two semi-infinite elastic plates connec ted by the vertical andflexural rotational springs as a model of a partial ly frozen crack in an ice sheet\; iii) afloating elastic platform of finit e length\; iv) two semi-infinite elastic plates separatedby a region of op en water (polynya). The hydrodynamic load (added mass anddamping coefficie nts) and the amplitudes of vertical displacements of the free surfaceand e lastic plates are calculated as functions of the cylinder oscillation freq uency andthe location of the cylinder with respect to the plate edges.

The 3-D problem is considered for time-periodic external pressure and a load uniformly moving along the rectilinear edge of the ice cover. By an alogy with the 2-D case\, the first two classes of hydroelastic system are considered\, as well as the effect of the solid vertical wall while the e dge of the ice cover adjacent to the wall can be either clamped or free. I n the problem of time-periodic external pressure\, it is shown that for se mi-infinite elastic plate contacting with free surface of water and for tw o non-identical semi-infinite plates\, divided by crack\, the directions o f predominantwave propagation are allocated under some angle to the crack. In the case of two identical semi-infinite plates\, divided by a crack\, the edge wave guide mode is excited.The edge wave is most excited is the c ase of semi-infinite plate with a free edge near a solid vertical wall.

In the case of moving load\, the 3-D pictures of generated waves in f luid and in ice cover are built for various speeds of motion. It is shown that in case of two identical semi-infinite plates\, divided by a crack\, two edge waveguide modes with different wave numbers exist for supercritic al values of speed motion. For the vehicle moving with supercritical speed one mode is extending in front of moving load and other mode behind it. T he wave forces acting on moving vehicle are investigated for \;various speeds of motion. LOCATION:Seminar Room 1\, Newton Institute END:VEVENT END:VCALENDAR