 One direction is the development of control-oriented nonlinear models 
and associated control design building on the Galerkin method, originally proposed by Boris Galerkin.He proposed the first mathematical Galerkin model for the two- and three-dimensional cylinder wake from Hilbert space considerations.Subsequent works employ the proper orthogonal decomposition and propose numerous enablers accounting for the pressure term, subscale turbulence and departures from the training set.