Simulation of environmental flows: Similarities and differences from technological flows

The most obvious and most important difference between technological and environmental flows is the length scales which need to be represented in the simulations. Other essential differences are that, on the smallest scales of environmental flows, the effects of stratification must be included and, on the larger scales, rotation plays a dominant role and must be accounted for. Another essential difference is that for many environmental flows it is essential to make forecasts-detailed predictions of the actual state (i.e., a single realization) for some time in the future. Thus, two types of simulations are performed: actual forecasts and simulations designed to produce data that will help simplify and reduce the cost of making forecasts. Several examples of the latter type are given in this paper: stratified sheared homogeneous turbulence, oscillating grid turbulence, oceanic upwelling, and Langmuir cells. They demonstrate the usefulness of small scale simulations in understanding and developing correlations for environmental flows.