Internal waves are oscillations on the interior density surfaces of stratified fluids. These waves are ubiquitous in the ocean and large lakes and are typically generated by surface winds or tidal flow up and over sloping topography. Between generation and dissipation, internal waves can redistribute momentum and energy across large distances (e.g. entire ocean basins), which can have important effects on climate, the accuracy of sonar, and offshore engineering. Cutting-edge simulations of internal waves require supercomputing resources because internal waves have small scales (1-100 km wavelength) and evolve rapidly (periods of minutes to hours), while traveling large distances (100-10,000 km) over long lifespans (days to weeks). In short, they require fine resolution over large domains and short timesteps over long integrations.