Numerical investigation of internal wave and free surface wave induced by the DARPA Suboff moving in a strongly stratified fluid

Numerical methods for simulating a strongly stratified flow were proposed based on a two-layer model. The VOF method was employed to trace the free surface and interface, and the SST model was used as the turbulence model. To verify the methods, numerical simulations of stratified flow around a cylinder were performed. Results were compared with relevant experiments. The near field around a 1:20 of the DARPA Suboff moving in a strongly stratified flow was simulated. The effects of pycnocline, submarine depth, and speed on the free surface wave and internal wave were analysed. The results demonstrate that the presence of pycnocline can increase the intensity of divergence and convergence at the free surface. Increasing the depth leads to a decrease of the free surface wave and shrinkage of the internal wave's scope. As the speed increases, the free surface wave shows a significant increase in wavelength and a decrease in Kelvin angle.