Positive and negative internal waves

The present study examines the propagation of long, nonlinear waves in the stably stratified two-layer system sketched in Figure 1. The bottom is taken to be rigid and the interaction with the atmosphere (y > h2) is ignored so that the free surface maintains a constant pressure. The densities in each region are taken to be constant and each fluid is regarded as inviscid. In the undisturbed state both fluids are taken to be at rest. (author)