Special Aspects of Transformation of Non-Linear Internal Waves on the Shelf and in a Deep Lake

The characteristic feature of stratified flows in large bodies of water is generation of intense short-period internal waves at the front of long-wave disturbances. The nonlinear processes are most pronounced during the propagation of bottom and near-surface disturbances. The effective tool for studying wave processes in the ocean is the theory of multilayer shallow water with regard for the effects of nonlinearity and dispersion. It is shown that the developed mathematical models are suitable for describing the transformation of nonlinear internal waves both in the shelf zone of the sea and in the deep freshwater reservoirs. In particular, the structure of near-bottom internal waves in the shelf zone of the Sea of Japan and recently discovered near-surface internal waves in Lake Teletskoye are compared. The mechanism of generation of intense internal waves during excitation of seiche oscillations in narrow water reservoirs is discussed. Traveling waves in a multilayer fluid are constructed and numerical solutions to the nonstationary problem of generating internal waves are found. A comparison with the laboratory experiments on generation of a packet of short-period internal waves during seiche oscillations of a two-layer fluid in a long channel, as well as with the recorded near-surface internal solitary wave in Lake Teletskoye, is carried out.