In this talk, we present and analyze some class of schemes based on a variant of the scalar auxiliary variable (SAV) approaches (Shen et al. (2018)) for some nonlinear problems. Precisely, we construct robust first and second order unconditionally stable schemes by introducing a new defined auxiliary variable to deal with nonlinear terms in gradient flows. The approach consists in splitting the gradient flow into decoupled linear systems with constant coefficients, which can be solved using existing fast solvers for the Poisson equation. We end the talk by given some results for the incompressible Navier-Stokes equations.