The hydrodynamic forces and flow fields of an underwater vehicle encountering internal solitary waves are numerically simulated by the Reynolds-averaged Navier–Stokes method. The Korteweg–de Vries internal solitary theory is used to model the induced currents. First, the general hydrodynamic characteristics are studied, and the computed results indicate that the unsteady feature of hydrodynamic forces is obvious under the action of internal waves. Second, three factors, such as the internal wave amplitude, underwater vehicle speed, and submergence depth, are investigated, and a series of cases are simulated and analyzed. Finally, the influence rules of the three factors are obtained with reasonable explanations.
An internal wave is a common marine phenomenon in the ocean, especially in the marginal seas. Figure 1 demonstrates the widespread occurrences of internal waves around the world. It is compiled by Jackson (2004), who identified more than 50 locations globally where internal solitary wave trains occur. In the density-stable stratified ocean, when the seawater tide flows through a dramatically changing terrain such as a submarine ridge, internal waves will be excited at the ridge (Fang and Du, 2005).