The following are explained: E-ε Model, E-l Model, Parameterized Length Scale Model, Parameterization of Turbulent Transport, Parameterization of Dissipation, Parameterization of Return-to-Isotropy Terms, Subgrid-scale models, Lagrangian Stochastic Models, Random-walk Model for Homogeneous Turbulence, Random-walk Model for Inhomogeneous Turbulence, and Short-Range Gradient Transport Models. In this research, the sequential approximation method was used as an alternative numerical method to solve the three-dimensional stochastic Langevin equation. After obtaining Langevin models for Gaussian, a comparison was made between the Copenhagen experimental data of Sulfur Hexafluoride (SF6). The two models are within a factor of two of the observed data, according to statistical assessments and stochastic analysis between the observed and predicted data. Additionally, the Correlation coefficient, Normalized Mean Square Error, and Fraction Bias are all in good agreement with the observed data.