Patch dynamics (physics)

Patch dynamics is a term used in physics to bridge, using algorithms, the models describing macroscale behavior and to predict large-scale patterns in fluid flow. It uses locally averaged properties of short space-time scales to advance and predict long space-time scale dynamics.
In patch dynamics and finite difference approximations, the macroscale variables are defined at the grid points of a mesh chosen to resolve the solution. The standard PDE [Adaptive Polygon mesh|mesh refinement|adaptive grid] methods can be used to resolve gradients in the macroscale solution. Both patch dynamics and finite difference methods generate time derivatives at mesh points; these time derivatives then help advance the solution in time.