In this talk, I will present the spatial and temporal scales of environmental fluids and the ongoing research topics in a view of ocean science and engineering ncluding (1)coastal oceanography and environmental science, (2)geophysical turbulent energy cascades at mesoscale and submesoscale, and (3)the site survey for the renewable energy (e.g., ocean tides and waves). These works are based on forward regional circulation model simulations forced with realistic wind stress, tides, and boundary conditions and remote sensing observations such as altimetry, geostationary ocean color imagery, and high-frequency radars.