Numerical simulations of sand wave formation by internal solitary waves

Deep-ocean sand waves are thought to be formed by high-energy internal solitary waves (ISWs) and can be tens of meters tall and hundreds of meters in length. These bedforms affect hydrodynamics, acoustics propagation, and buried infrastructure, yet their formation mechanisms are poorly understood. We develop a method to initialize large-amplitude ISWs in a generalized vertical coordinate, nonhydrostatic ocean model with a Dubreil-Jacotin–Long (DJL) solver. A bed evolution equation that includes bedload transport and avalanching allows sand waves to evolve in response to the ISW-induced bottom stresses. Simulations are performed for a range of background stratifications to examine the relationship between properties of ISWs and the wavelengths of the resulting sand waves.