Velocity Propagation of Waves at the Interface of Two Liquids for the Case of Large Wave Length

The surface waves occur at and near the free surface of an unbounded sheet of liquid which is irrotational incompressible and two-dimensional. To illustrate the waves at the interface of 2 liquids, the progressive waves and stationary waves on the surface of a canal and on a deep canal are also considered. For the convenience of our calculation, Bernoulli s equation is taken and then at steady state the velocity propagation is obtained. In fact, we have generalized velocity propagation when wave length is large compared with thickness between 2 layers.