Subgrid models is a class of parameterized formulations within computational science and numerical simulation, designed to represent the collective or statistical effects of physical processes or structures that occur at scales below the resolution of the simulation grid. This methodological approach is essential for enabling computationally feasible simulations of complex multi-scale systems across diverse fields, including astrophysics, geophysics, and environmental modeling, by capturing the impact of unresolved phenomena on the larger, resolved scales.